When Is a Nutrient an Antinutrient?

Antinutrients, like phytates, oxalates, and glucosinolates, are components of food or dietary nutrients that interfere with absorption of other nutrients. In this article, we’ll cover the latest findings on how antinutrients affect your health so you can separate fact from fiction as you continue seeing news coverage on this hot topic.

If you’re interested in optimizing your diet, you’ve likely encountered the word antinutrients before. Certain experts have raised concerns about antinutrients, components of food or dietary nutrients that interfere with the absorption of other nutrients. Different antinutrients, such as phytates, oxalates, and glucosinolates can be found in various types of food, including fruits, veggies, legumes, dairy, and meat.

At this time, the long-term impact of antinutrients on human health has yet to be fully sussed out. Research has shown that while antinutrients can cause health problems, they can also bring health benefits. The majority opinion among health authorities at this time is that the advantages of eating foods containing antinutrients outweigh the adverse effects of forgoing those foods altogether.

Read on to learn more about antinutrients and how they affect your health so you can separate fact from fiction as you continue seeing news coverage on this hot topic.

What Are Antinutrients?

The answer to the question of what antinutrients are can be found in the name itself: while the term nutrients describes substances that provide the raw materials plants and animals (humans included) need to thrive, antinutrients prevent them from absorbing and utilizing those substances. In short, they block the absorption of nutrients. Antinutrients occur naturally in a variety of both plant-based and animal-based foods.

The purpose of those found in plants, like lectins, is to prevent bacterial infections and protect against consumption by predators, as an article published in Plant Physiology outlines. To illustrate that idea, consider the case of the nightshade family of vegetables, which includes potatoes, tomatoes, peppers, and eggplants. All nightshade vegetables contain solanine and chaconine, antinutrients intended to deter animals and humans alike from consuming them as they can make you sick when ingested in large doses.

A common health concern raised by those worried about antinutrient consumption is that ingesting high amounts can result in nutrient deficiencies, particularly for individuals adhering to diets that classify certain foods as off-limits, particularly vegan or vegetarian diets organized around legumes and grains. Another worry is that they may increase intestinal permeability, resulting in a health condition referred to as leaky gut.

Fact-Checking Concerns About 7 Antinutrients

As described above, antinutrients impede the body’s ability to absorb essential nutrients such as vitamins, minerals, amino acids, and so on. While this clearly has the potential to be problematic, the evidence so far indicates that it’s unlikely to cause issues in the absence of overall malnutrition or dietary imbalances. Furthermore, studies show that in certain circumstances, antinutrients can actually enhance a person’s health—for instance, tannins found in tea can decrease cancer risk and phytic acid can lower cholesterol and triglyceride levels.

In the sections below, we’ll delve into the details of common concerns raised about seven of the most significant antinutrient groups:

  1. Lectins
  2. Phytates
  3. Oxalates
  4. Tannins and other flavonoids
  5. Glucosinolates
  6. Enzyme inhibitors
  7. Saponins

1. Lectins

Lectins can be found in all plants but in particularly high concentrations in seeds, legumes (most notably kidney beans), and whole grains as they tend to cluster in the parts of seeds that go on to become leaves after sprouting occurs.

In the popular consciousness, lectins have entered into the same category as gluten: a poorly understood substance widely believed to be, somehow, bad.

Going “lectin-free,” in the way you might go gluten-free, is posited as a way to prevent leaky gut syndrome. The theory is that when you eat foods that contain high amounts of lectin, the lectin proteins bind to cells in the walls of the digestive tract where they then create minute punctures that allow the contents of the gut to leak into the bloodstream. In high amounts, lectins may also prevent the proper absorption of certain nutrients, including calcium, iron, phosphorus, and zinc.

According to a literature review published in the American Journal of Clinical Nutrition, some lectins do have “deleterious nutritional effects.” The review also notes that dietary exposure to lectins appears to be widespread. However, the authors could not decisively determine whether lectins caused noticeable health issues.

A separate article states that due to the “ubiquitous” presence of lectins in plants, we all ingest them daily in “appreciable amounts”—unless, of course, you’re taking steps to avoid them. The article goes on to explain that it is the ability of lectins to remain intact in the digestive tract that allows them to cause damage to its lining, though the effects it notes do not include the development of leaky gut, but rather:

  • Loss of gut epithelial cells
  • Damage to the membranes of the epithelium
  • Impaired digestion and absorption of nutrients
  • Disruption to balance of bacterial flora and immune state of the gut

Before you begin to panic about the logistical challenges of avoiding lectins, remember that researchers have yet to find conclusive evidence that consuming lectin-containing foods produces damage significant enough to impact the well-being of individuals who are otherwise in good health.

Phytates

Also called phytic acid, these antinutrients can be found in many of the same foods as lectins—think legumes such as lentils, nuts, seeds, whole grains, and pseudocereals like quinoa. Their purpose for the foods that contain them is to provide the phosphorous necessary for the growing plant.

Studies show that phytates interfere with the absorption of certain minerals and trace elements, including calcium, iron, magnesium, and zinc, by binding to those micronutrients during digestion.

However, an article published in Molecular Nutrition & Food Research notes that dietary phytates also have beneficial effects such as decreasing the likelihood of kidney stone formation and keeping blood sugar and blood lipid levels in the healthy range. The authors note, too, that phytates appear to have antioxidant and possibly anticancerogenic properties.

So, it seems that the phytate content of a food should certainly not be a cause for concern and may even be a boon to your health.

Oxalates

Oxalates, or oxalic acid, can be commonly found in nuts and seeds as well as in leafy greens, fruits, vegetables (particularly rhubarb), and cocoa. Oxalates bind to minerals to form calcium oxalate or iron oxalate. This makes it much more challenging for the body to absorb those minerals.

A review published in the American Journal of Clinical Nutrition compared the absorbability of calcium from spinach, which contains oxalates, to that of calcium from milk, which does not, and found that the absorption from milk was always higher. The mean absorption for milk was 27.6% while spinach achieved a mere 5.1%.

In some instances, oxalates have also been linked to an elevated risk of kidney stone formation, though thanks to the high nutritional value of oxalate-containing foods, physicians no longer universally recommend low-oxalate diets to those with kidney stones. In other words, there’s no need to try to avoid oxalate-rich foods due to this possible side effect. Most people will harm their health more by avoiding these healthful foods than by ingesting the oxalates they contain.

Tannins and Other Flavonoids

You may be confused to see flavonoids on this list, as this group of naturally occurring polyphenols (which include tannins) have often been discussed as nutraceuticals because of their antioxidant properties. However, these compounds, like the other antinutrients, chelate or bind with minerals such as iron and zinc and reduce the absorption of these nutrients.

For instance, the tannins found in tea, coffee, fruit skins, and legumes have been linked to decreases in iron absorption. Yet they have also been shown to have anticarcinogenic activity and to inhibit the growth of fungi, bacteria, and viruses.

One way to think about tannins, as an article published in Trends in Food Science and Technology aptly put it, is as “a double-edged sword.” It appears, however, that consuming small quantities of tannins will allow you to access their benefits, while larger amounts are needed before the threshold for adverse effects is crossed.

Glucosinolates

These antinutrients are found in high amounts in cruciferous vegetables like broccoli, Brussels sprouts, and cabbage. Like tannins and the rest of the flavonoid family, you may be more familiar with glucosinolates as a desirable phytonutrient.

Yet the same compounds renowned for their ability to help prevent cancer also impede iodine absorption, which can lead to an iodine deficiency and impaired thyroid function. Individuals whose diets contain insufficient amounts of iodine or who have hypothyroidism (underactive thyroid) are most at risk for this issue.

There’s also some indication of an association between a greater intake of glucosinolates and a higher risk of type 2 diabetes. Studies so far, such as this one from 2018, have all been population-based, making it too early to say whether there’s a causal relationship at work.

Enzyme Inhibitors

This category of antinutrients includes protease, amylase, and lipase inhibitors, all of which impact the body’s ability to digest and absorb macronutrients. They can be found in a wide swathe of the plant kingdom, including legumes, seeds, and whole grains.

A protease is an enzyme (the -ase ending in chemistry denotes an enzyme) that helps break down proteins, amylase is an enzyme that breaks down certain carbohydrates, and lipase is an enzyme that breaks down lipids (fats). If the enzyme is “inhibited,” it is prevented from breaking down the macronutrient and making it available for absorption. Therefore, protease inhibitors make the body less able to digest protein, amylase inhibitors do the same for carbohydrates, and lipase inhibitors do so for fat.

Food sources of protease inhibitors include beans and other legumes, cucumbers, radishes, broccoli, spinach, potatoes, and egg whites, which contain a trypsin inhibitor along with avidin, which interferes with biotin absorption.

Interestingly, both amylase and amylase inhibitors are touted as having health benefits. Natural dietary sources of amylase include raw fruits and vegetables, along with sprouted seeds, nuts, legumes and whole grains. Amylase inhibitors are found in Garcinia cambogia, guar, inulin, Rosmarinic acid, and other plant foods.

Lipase inhibitors, as already noted, interfere with the enzymes we use to process fats. Lipase inhibitors do not discriminate between fats, meaning absorption of good fats like omega-3 can be compromised. However, they can also be beneficial in that they protect the body from absorbing harmful fats. For that reason, the FDA approved a prescription lipase inhibitor called Orlistat that can increase weight-loss results by allowing fats to pass through your system unprocessed. Orlistat can also beneficially lower total cholesterol and low-density lipoprotein, return blood pressure levels to the healthy range, and regulate fasting glucose and insulin concentrations.

Saponins

Saponins are perhaps best known for their ability to produce soapy foam when shaken with water. They can be found in a range of legumes and whole grains and can interfere with normal nutrient absorption. Per an article published in the International Journal of Nutrition and Food Sciences, they may also inhibit the actions of various digestive enzymes in the same manner as the substances discussed in the preceding section, thereby decreasing protein digestibility.

However, that same article notes that there’s evidence saponins lower cholesterol. An article published in the Journal of Medicinal Food went even further, describing saponins as “health-promoting components” and praising them for their ability to decrease your risk of cancer.

Other Antinutrients You May Encounter

In addition to the seven antinutrients discussed above, you may see references to other antinutrients. Keep in mind that what findings exist about their impact on human health likely show the same complicated and contradictory results. With that said, here are several other antinutrients as well as some food sources for each:

  • Allicin and mustard oil: Alliums like chives, leeks, onions, scallions, shallots, and garlic
  • Alpha-amylase inhibitors: Whole grains, legumes, the skins of various nuts, and the leaves of the stevia plant
  • Calcitriol, solanine, nicotine: Nightshade vegetables like eggplant, peppers, tomatoes as well as goji berries
  • Goitrogens: Cruciferous vegetables, soybeans, and peanuts
  • Oligosaccharides: Wheat, legumes, asparagus, and alliums
  • Salicylates: Berries and other fruits like apricots as well as some herbs and spices including cayenne, ginger, and turmeric
  • Uric acid: Primarily animal-based foods like meat (particularly organ meat), eggs, and dairy as well as legumes and some vegetables

14 Common Antinutrients and the Foods You'll Find Them In

How Antinutrients Affect Your Health

It’s challenging to speak generally about the health effects of antinutrients since they depend on an individual’s metabolism, how the food is cooked and prepared, and the presence of any food sensitivities, nutrient deficiencies, or health conditions.

Keep in mind, too, that many dietary substances can act as antinutrients under certain circumstances.  For example, alcohol, when consumed in excess, interferes with the bioavailability of zinc and the B vitamins.

Also, the antinutrient only impairs the absorption of nutrients that are co-ingested in the meal. For example, a phytate-rich snack of raw almonds won’t affect the absorption of iron from a steak consumed later in the day.

There are many other strategies to “neutralize” the antinutrients found in foods. Many culinary techniques such as soaking, fermenting, and sprouting (and, of course, cooking) of beans and seeds are common approaches that increase the palatability and nutrient availability.

In a balanced, omnivorous diet, antinutrients present no problem, and the benefits they confer, such as antioxidant properties and removal of toxic metals, far outweigh any impact on mineral balance.

Vegetarian or vegan diets, on the other hand, may involve the combination of low intake of iron, zinc, and calcium and a high consumption of grains that contain phytates and other antinutrients. The result of this combination can be dietary deficiencies in minerals that, over time, lead to a deficiency. These mineral imbalances result in impaired immune function, anemia, and poor bone health, among other symptoms.

That said, there’s some indication, like this study done in 2012, that the bodies of individuals adhering to such diets may adapt over time to the continued presence of antinutrients by becoming more efficient at metabolizing minerals such as iron and zinc.

Individuals with an elevated risk of developing conditions linked to mineral deficiencies, such as osteoporosis or anemia with iron deficiency may wish to consult a dietitian or nutritionist to develop an eating approach designed to improve mineral absorption. Such a strategy might be to reduce antinutrients, but that’s certainly not the only method. You might instead strategically time intake of foods with high antinutrient content, such as tea, to avoid impeding mineral absorption, or plan to take a high-quality calcium supplement after consuming a legume dish high in phytates.

It’s also worth noting that antinutrients can largely be minimized by food processing and by genetic engineering. In countries with less industrialized agricultural systems, antinutrients have presented nutritional problems, but in the United States, most diets contain micronutrients in amounts well above the minimal requirement.

Interestingly, the tendency to put more and more focus on the benefits of unprocessed fruit, vegetables and grains, increases the likelihood that antinutrients could undermine a well-intended dietary plan.

As established in the last section, antinutrients often have health benefits of their own. While it’s true that phytates interfere with calcium absorption, they also manage the body’s rate of digestion, forestalling blood sugar spikes. Because antinutrients can be quite good for you, most experts do not recommend that you avoid consuming them entirely.  As long as you eat foods with a high antinutrient content in the context of a nutritious, varied diet, there’s very little risk involved.

Conclusion

So, should you worry about  antinutrients? The simple answer is that they don’t need to be a problem if care is taken in preparing foods and timing the ingestion of raw foods and snacks apart from mineral-dense meals or dietary supplements. Certain foods will likely contain some antinutrients no matter how you process and prepare them, however, the nutrients found in those foods will typically have a more pronounced effect than the antinutrients. By eating a wide assortment of foods each day, and taking care not to eat meals centered on a large portion of a food source of antinutrients, you should be able to offset any potential adverse effects of antinutrients.

EAA Supplements: The Best Amino Acids for Muscle Growth

The best amino acids for muscle growth tip the balance in favor of muscle protein synthesis. And making a complete protein requires adequate availability of each of the amino acids. Read on to find out the formulation of amino acids that is best for building muscle.

Before we get into the best amino acids for muscle growth, let’s first review the makeup of muscle. Muscle tissue is composed of a variety of proteins that are in a constant state of turnover—proteins that are no longer functioning well are being broken down and new ones are being produced. Muscle growth occurs when the rate of synthesis of new muscle protein exceeds the rate of breakdown.

Muscle protein is composed of 20 different amino acids hooked together in a specific order. Nine of the amino acids are essential amino acids (EAAs) and cannot be produced in the body. The other 11 are nonessential (NEAAs) and can be produced in adequate amounts within the body.

Muscle protein synthesis (the building of new muscle protein) involves a series of molecular events that result in the component amino acids being linked together in a specific order. For this reason, amino acids are often called the building blocks of protein. Making a complete protein, therefore, requires adequate availability of each of the amino acids. In that sense, there is no individual best amino acids for muscle growth, because they are all required to produce muscle protein. Rather, there are formulations of amino acids that are “best” for specific circumstances, such as building muscle.

Where Do Amino Acids Come from for Muscle Protein Synthesis?

When protein is broken down during muscle protein turnover, amino acids are released into muscle cells. Most of these amino acids become the precursors for the synthesis of new muscle protein. However, some of the amino acids from protein breakdown are released into the blood and delivered to other tissues and organs, and still other amino acids from protein breakdown are irreversibly oxidized/damaged. Therefore, the rate of reincorporation of amino acids from protein breakdown into newly synthesized muscle protein will always be less than the rate of protein breakdown. Without other sources of amino acids, a reduction of muscle protein and subsequent muscle loss occurs.

There are two ways to get the additional amino acids you need for muscle protein synthesis.

  1. They are produced in the body. (NEAAs can be produced in the body, so only a minimal amount must be consumed in the diet to meet all demands.)
  2. EAAs, on the other hand, cannot be produced in the body and must be consumed in the diet.

Research shows that consuming EAAs stimulates muscle protein synthesis and helps build muscle, but eating more NEAAs doesn’t add any further stimulus. When EAAs are consumed, the additional NEAAs required for the production of complete proteins are produced in the body. Ingesting EAAs, either as dietary protein or as amino acid supplements, shifts the balance between synthesis and breakdown of muscle protein to favor the net production of new muscle protein, which defines muscle gain.

What Are the Best Amino Acids for Muscle Growth?

Muscle protein is composed of a specific amount of each amino acid, hooked together in a specific order. In that sense, all the amino acids are equally important, as a shortage of any of them will stop the process of synthesis.

The EAA in shortest supply is called the limiting EAA. The availability of the limiting EAA will limit the rate of muscle protein synthesis, regardless of the availability of all the other EAAs and NEAAs. Therefore, you could say that the limiting amino acid in any formulation of EAAs is the most important.

This is the major problem with supplements that only have the branched-chain amino acids (BCAAs) leucine, isoleucine, and valine. Since the other essential amino acids are not provided, the rate of muscle protein synthesis is not improved. Because of this, BCAA supplements have been proven to provide a far smaller effect on muscle growth than a complete EAA formulation.

It is possible to gain insight into the amount of each EAA that is needed to avoid that EAA being the limiting EAA by looking at the requirements for the individual EAAs. By definition, NEAAs are not required in the diet, so when we talk about dietary requirements we are talking only about EAA requirements. The dietary requirement for each EAA differs. Here are the daily requirements for EAAs for adults as published by the Food and Agriculture Organization of the World Health Organization (FAO/WHO).

Best Amino Acids for muscle growth

The requirements are based on a number of factors, including the composition of total body protein. From the requirements shown above, it is clear that all EAAs are not “equal.” The requirements for leucine and lysine are the highest, while the requirement for tryptophan is quite low.

It could be argued that the best amino acids for muscle building parallel the individual requirements of the EAAs. Indeed, that is the basis for the official FAO/WHO grading of protein quality, called the Digestible Indispensable Amino Acid Score (DIAAS). Indeed, an EAA supplement that closely parallels this distribution will be an effective stimulant of muscle protein synthesis in any circumstance. The bottom line is that you need all the essential amino acids to have any effect on muscle mass, and any nonessential amino acid need not be included in a dietary supplement.

Leucine for Muscle Growth

There has been considerable research over the past 15 years that indicates that alternative mixtures of EAAs may be more beneficial in particular circumstances. Most of the research has centered on the EAA leucine. In addition to being the most abundant EAA in body protein, under certain circumstances, leucine can function to regulate molecular processes within the muscle cell. In those circumstances, it can be called a “nutraceutical.”

Leucine can activate the molecule called mTOR, which gets muscle protein synthesis started. Various conditions associated with progressive muscle breakdown and loss of muscle strength, such as cancer, heart failure, and aging, can suppress the activity of mTOR and associated molecules. When mTOR activity is limited, it may be preferable to increase the proportion of leucine to as high as 35% to activate mTOR. At the same time, activation of mTOR and associated molecules in the muscle cell is not sufficient to increase muscle protein synthesis. You also need an abundance of all EAAs to produce complete proteins. Therefore it is necessary to limit the proportion of leucine in an effective dietary supplement to below 40% so that sufficient amounts of the other EAAs can be included.

If extra leucine is added to a dietary supplement such as whey protein powder to capitalize on its action as a nutraceutical, then the remainder of the supplement should provide the other EAAs in proportion to their contribution to the composition of muscle protein. It seems logical that this would be dictated entirely by the composition of muscle protein, but it is not quite so straightforward.

The absorbed ratios of the different EAAs will not be directly reflected in the EAAs inside the muscle cells because some amino acids are transported into the cell faster than others. Lysine, in particular, is transported sluggishly into the muscle. When lysine is consumed, less lysine will enter the muscle cell than would be expected from the profile of the consumed EAAs. Consequently, to increase the lysine concentration inside the muscle cell in proportion to the lysine content of muscle protein it is necessary that lysine comprise 20% or more of the total EAAs consumed to achieve the maximal muscle-building effect.

Different Strokes for Different Folks

The most effective EAA supplement for muscle growth will have all the EAAs and roughly parallel the requirements cited above. However, alternative formulations may be “best” in different situations. For example, while a high proportion of leucine may be best for older individuals with heart failure, a disproportionate amount of leucine may not be needed by a young athlete after a resistance workout. This is because the resistance workout will activate mTOR and associated molecules, and if the proportion of leucine is in line with the composition of muscle protein (around 23%), then relatively more of all the other EAAs needed to produce complete protein can be included in the supplement.

Even the optimal formulation for exercise might vary, depending on when the supplement is consumed and the type of exercise. For example, endurance training causes a selective increase in leucine oxidation, in which case a supplement high in leucine would be optimal as a post-workout supplement following exercise to speed up muscle recovery.

If the EAA supplement is meant to be consumed as a pre-workout supplement for exercise performance, it may be formulated to optimize the concentrations of neurotransmitter precursor availability in addition to providing EAAs for muscle protein synthesis.

Regardless of the specific circumstance it is meant for, the “best” formulation will include all the EAAs and not just the BCAAs or specific amino acids like beta-alanine or arginine. A complete formulation will more effectively stimulate the production of new muscle protein than any individual or sub-group of EAAs possibly can.

How to Use Amino Acids for Bodybuilding

Amino acids have become some of the most popular types of bodybuilding supplements across multiple disciplines. Both BCAAs and EAAs can be used on their own or in the form of “stacks”—specialized blends of multiple supplements that work together synergistically to provide even greater benefits than when taken on their own.

Bodybuilding usually refers to increasing and sculpting muscle mass for appearance as well as strength. In a more general sense, bodybuilding can refer to increasing muscle mass and function for the purpose of competing in sports such as football or power sports (e.qg., shot putting, discus throwing, etc.). It is a given that bodybuilding requires resistance training. If bodybuilding is for the purpose of improving competitive performance in a specific sport there are likely to be training requirements unique to that sport. This discussion on amino acids for bodybuilding will, therefore, not focus on the specific aspects of training. Regardless of the goal of training, amino acids play a key role in bodybuilding.

The Impact of Nutrition on Bodybuilding

Training tends to be the first factor most consider when seeking to build lean muscle, however, the nutrients we provide our bodies with can be equally influential—or more so—in determining how quickly we progress toward our goals. No matter how intensely you train, you will not be able to achieve the results you desire if you’re lacking certain crucial nutritional elements.

Obtaining all the nutrients you need from your diet alone in the quantities necessary for maximal bodybuilding results can be challenging. That’s where workout supplements come in.

By taking targeted sports nutrition supplements, you can ensure you get all the nutrients you need to build muscle, speed recovery time, decrease muscle soreness, amp up energy levels, and more.

Bodybuilding Supplements Then and Now

Depending on how broadly you interpret the idea of dietary supplementation, the idea of bodybuilding supplements can be traced back to ancient Greece.

According to Professor Andrew Dalby and other experts, Greek and Roman athletes consumed large quantities of meat and wine as well as herbal concoctions and tonics with the goal of increasing their strength and stamina.

In the early 1900s, Eugen Sandow, a pioneering German bodybuilder whose legacy earned him the honorific “father of modern bodybuilding,” advised all who wished to maximize their muscle growth to adhere to the dietary rules he himself followed. Bodybuilder Earle Liederman, who rose to prominence in the 1920s, recommended drinking what he called “beef juice” or “beef extract” (a substance the luminaries of today’s wellness landscape call “bone broth” and chefs simply refer to as “consommé) in order to speed muscle recovery.

In the 1950s, protein powders entered the picture as recreational and competitive bodybuilding became ever more popular with ever-broader audiences in the United States and elsewhere. Irvin P. Johnson, who operated a bodybuilding gym in Chicago, was one of the first to market egg-based protein powder. According to an article he published in Iron Man with the title “Build Bigger Biceps Faster with Food Supplements,” his specialized line of protein powders fueled serious strength gains. According to the article, he went from only being able to leg press 165 pounds for 10 repetitions to 660 pounds for 12 repetitions!

The bodybuilding supplement industry grew at an exponential rate throughout the 1970s and 1980s, fueled both by increased interest in recreational bodybuilding as well as advancements in advertising. Then, in October of 1994, Congress passed the Dietary Supplement Health and Education Act, a piece of legislation that transferred responsibility for determining the safety of dietary supplements such as protein powders and other mainstays of sports nutrition from the government to the manufacturers of the products. Unless they added a new dietary ingredient, manufacturers were no longer required to provide the U.S. Food and Drug Administration (FDA) with evidence to substantiate the safety or efficacy of their products. Legal experts believe this opened the door for the supplement industry to sell even more of their products. According to a Consumer Reports publication, annual sales of sports nutrition supplements hit $2.7 billion in 2010. And according to the “Sports Nutrition and High Energy Supplements – Global Market Outlook (2017-2026)” report sports nutrition and high energy supplements made $44.58 billion in 2017 with an outlook of $124.85 billion by 2026.

Defining the Term “Bodybuilding Supplements”

Just as the term bodybuilding can encompass both physique-focused and performance-focused endeavors, so too can the term “bodybuilding supplements” encompass a multitude of dietary supplements utilized by individuals engaged in bodybuilding as well as weight lifting, mixed martial arts, and other athletic pursuits to increase lean body mass as well as bring about other desirable outcomes such as:

  • Decreased body fat
  • Sharper muscle definition
  • Enhanced athletic performance

Amino acids have become some of the most popular types of bodybuilding supplements across multiple disciplines. Both branched-chain amino acid supplements (BCAA supplements) and essential amino acids (EAAs) can be used on their own or in the form of “stacks”—specialized blends of multiple supplements that work together synergistically to provide even greater benefits than when taken on their own.

Making the Most of the Building Blocks of Protein

Amino acids have earned the nickname “the building blocks protein” because of the vital role they play in creating muscle tissue. While it’s certainly possible to obtain all the amino acids you need simply by eating high-protein foods like eggs, lean meats, legumes, vegetables, and pseudo-grains like quinoa, amino acid supplements can be a convenient and efficient way to maximize the benefits of amino acids.

One of the most compelling reasons to use supplements can be captured in a single word: bioavailability. Bioavailability refers to how efficiently a substance can be metabolized and the percentage of what’s ingested that’s utilized for its intended purpose inside the body.

Several factors determine the bioavailability of each amino acid. For example, when taking in amino acids from a food source, the amount of fat contained in that food influences the length of time it takes for amino acids to be put to use. The way you cook food can also impact the amino acids it contains. Some heat-sensitive amino acids can even decompose when cooked. And not all amino acid supplements are metabolized at the same rate. The physical nature of the supplement will have the most significant influence on its bioavailability. A BCAA powder, for instance, will be digested differently than a supplement in pill or liquid form. The extent to which a supplement is pre-digested as well as whether it contains any fillers or binders impact its overall bioavailability.

Understanding Muscle Protein Turnover

Muscle protein turnover is the metabolic basis that powers increased muscle mass, strength, and function.

Muscle protein turnover refers to the constant breakdown of older muscle proteins that are no longer operating at peak efficiency and their replacement with newly synthesized, more efficient muscle protein fibers. The balance between protein synthesis and breakdown determines whether a muscle is growing or shrinking.

Muscle function is accomplished by the contraction of muscle protein fibers. Muscle strength and function are determined by how many muscle protein fibers you have and the efficiency with which they contract. Increasing muscle protein mass and contractile efficiency is accomplished by optimizing muscle protein turnover.

For bodybuilding, the goal is to make the rate of muscle protein synthesis exceed the rate of protein breakdown. Further, the increased balance between muscle protein synthesis and breakdown should optimally be accomplished mainly by stimulating synthesis, not lessening breakdown—protein breakdown gets rid of muscle proteins that are not functioning efficiently, so it is good to keep that process functioning at full speed.

The Mechanics of Muscle Protein Synthesis

Muscle proteins are composed of a series of amino acids hooked together in a specific order determined by the messenger RNA (mRNA) in the cell for each specific muscle protein. The sequence of the mRNA is dictated by the DNA in the cell. There is a specific molecule for each amino acid (tRNA) that delivers it to the mRNA as required for incorporation into the protein that is being produced.

A simple, conceptual way to think about the process of muscle protein synthesis is to compare it to the construction of a building. The DNA is basically the idea for the design of the building. The RNA is the written plan or blueprint, and transcription of the mRNA from the DNA is the process of writing up the plan. The tRNA molecules that bring the amino acids to the mRNA for incorporation into protein are like trucks that bring bricks to the building site, and the hooking of amino acids together in the proper order on the mRNA corresponds to the builder putting the bricks together according to the blueprint. The protein is the final product, or completed building, ready to serve its function.

The details of how muscle protein is made are important only so that it is clear why all the amino acids must be available in abundance. If the mRNA dictates that the next amino acid in the chain making up the protein is a particular amino acid that is deficient, then the process is halted and no muscle protein is produced.

How Amino Acids Impact Muscle Protein Synthesis

We must derive certain amino acids, as I touched on earlier, from dietary protein. However, the human body can synthesize other amino acids through chemical reactions that occur in the liver and select sites throughout the body.

The amino acids that must be obtained from the diet are called essential amino acids, or EAAs, while the amino acids that can be made in the body are called nonessential amino acids, or NEAAS.

The nine essential amino acids are leucine, isoleucine, valine, phenylalanine, lysine, methionine, phenylalanine, threonine, and tryptophan. Three of the EAAs, leucine, isoleucine, and valine, have been subcategorized as branched-chain amino acids (BCAAs), a descriptor which refers to their chemical structure. We typically put the number of nonessential amino acids at 11, as that’s how many NEAAs can be found in human protein, though other NEAAs like citrulline and ornithine can be found elsewhere in the body.

Since your body can produce NEAAS and they are available in abundance, the availability of EAAs serves as the limiting factor for setting the rate of muscle protein synthesis.

Using Essential Amino Acids to Stimulate Muscle Growth

Consuming essential amino acids, either as dietary protein or supplements, is the most potent stimulus of muscle protein synthesis. Consuming nonessential amino acids, either alone or with EAAs, has no impact.

EAA supplements have been shown to trigger muscle protein synthesis and increase muscle mass, strength, and physical function in at least 25 clinical trials. The muscle-building response to EAAs is 2 to 4 times greater than the muscle-building response to the same amount of a whey protein supplement. The muscle-building response to EAAs is even greater than the response to hormonal treatment with testosterone, growth hormone, or insulin.

There is one very big must when it comes to EAA supplementation, however. In order to be effective, all the EAAs are required. That being said, there are varying degrees of importance among the EAAs.

Leucine, which is both an EAA and a BCAA, is particularly important. Leucine is the most abundant EAA in muscle protein, so it should comprise the highest proportion of an EAA supplement. Beyond its role as a component of muscle protein, leucine can signal the molecular mechanisms within the cell to initiate the process of protein synthesis. Important as leucine may be, however, it cannot function alone. All the other EAAs are required as well, roughly in proportion to their relative content in muscle. It is not possible to make muscle protein from leucine alone.

The Role of Essential Amino Acids for Bodybuilding

It is clear from the above discussion that making sure you consume enough essential amino acids is an important part of bodybuilding. Even when using EAA supplements, the main source for your essential amino acids intake will likely be dietary protein. Therefore, the place to start is with your diet.

Protein is the key dietary component of the basic bodybuilding diet. It will increase your muscle mass. You should set a goal of eating approximately 30% of your caloric intake as high-quality protein.

When I say high-quality protein, I mean a protein that contains a high abundance of essential amino acids. High-quality proteins are generally animal-based proteins. These protein food sources also have a significant amount of non-protein calories. Therefore, eating a sufficient amount of high-quality protein to supply all the EAAs you need is difficult through normal diet alone.

You will most likely run into issues with the flexibility of your diet when eating this amount of high-quality protein food sources because of the non-protein calories. Therefore, EAA supplements can play a vital role in helping you meet your dietary goal for EAA intake.

While the focus of your basic diet should be high-quality protein, you must remember that energy substrates (carbohydrates and fat) are important too. As an example, in a tightly controlled study, subjects drank the same amount of protein in the form of milk. In one case, it was skim milk, and in the other case whole milk. The stimulation of muscle protein synthesis was greater with the whole milk. Under these study conditions, the additional calories provided by the fat in the whole milk helped to fuel muscle building.

You must be in a positive energy balance to gain a significant amount of muscle mass. Carbohydrate is of less importance for resistance training than it is for endurance training, but you should eat enough fruit and vegetables to meet the RDAs for micronutrients. Also, carbohydrate intake will stimulate insulin release, and insulin is an anabolic hormone that will increase the amount of muscle protein made from your EAA intake.

Fat intake will also amplify the anabolic effect of EAAs, and therefore you can eat animal-based, high-quality protein foods without worrying about eating too much fat.

What you do want to keep in mind with your bodybuilding diet is that the more you eat, the bigger you will get. If you do eat a lot while lifting heavy weights and consuming EAA supplements as recommended, a significant part of the weight gain will be muscle.

You will also gain fat with this dietary approach, so you need to carefully monitor your body composition to be sure that the extra fat you put on does not counteract the benefits of the muscle gain. In a sport like powerlifting, that is not likely to be the case, but if you are bodybuilding for appearance, you must reach a balance between muscle and fat gains. This can be accomplished by incorporating aerobic exercise into your training program.

How to Use Essential Amino Acids for Optimal Bodybuilding Results

amino acids for bodybuilding

The research documenting the optimal use of amino acids for bodybuilding is extensive. Experts can provide precise guidance on the effects of taking EAAs both pre-workout and post-workout.

Consuming 15 grams of EAAs 30 minutes before starting your workout will elevate blood concentrations of essential amino acids throughout your workout and stop the muscle breakdown that would otherwise occur. A 15-gram dose of EAAs achieves a greater response on muscle protein synthesis than either casein or whey protein can, without creating the fullness that can hinder a workout.

Then immediately after your workout, take another 15 grams of EAAs. One hour later, take another 15-gram dose.

These recommendations stem from the assumption that you will be working out every day. When you do take off days, you should still consume the same amount of EAAs. Instead of using your workouts to determine the timing, however, take your EAAs between meals.

Between the completion of dinner and breakfast the next morning, you may go for 12 hours or more without food. During this post-absorptive time, muscle tissue breakdown transpires in order to supply amino acids to tissues and organs that have no protein reserve. Therefore, to fuel maximal muscle-building response around the clock, you should consume another 15 grams of EAAs before bedtime. If you have wholly committed to maximizing muscle gain, you can even set your alarm for a final dose at about 4 am.

Alternatively, you can take 20 grams of casein protein at bedtime. Because casein coagulates in the stomach, your body digests it at a slower rate, meaning the amino acids it contains are then absorbed over many hours. While the anabolic effect will be less than if you take the EAAs, this approach will save you the trouble of getting up in the middle of the night.

The total amount of supplemental EAAs you ingest should be in the range of 60 grams per day. Consuming this amount of EAAs will stimulate the production of new muscle protein without you having to also take in a significant amount of non-protein calories. The result will be a lean body with increased muscle mass and minimal increase in fat mass. Sixty grams of EAAs in addition to what you eat as part of your bodybuilding diet is needed to drive protein synthesis past what may be your normal genetic limit.

Do EAA Supplements Have Side Effects?

This a reasonable question, because bodybuilding requires a much higher than average EAA intake. An important caveat to state up front is that I am focusing exclusively on side effects from EAA supplements.

When your EAAs come from an unusually high amount of dietary protein intake, that will increase the rate of amino acid oxidation and as a result, burden the kidneys to excrete the ammonia and urea that are natural byproducts of NEAA oxidation.

The great thing about EAA supplements, however, is that there is no such increased oxidation of NEAAs when EAAs are consumed. This is because NEAAs are not also being consumed but are rather being produced in the body. In fact, the oxidation of the NEAAs actually goes down, since they are being incorporated into protein at an increased rate.

Consequently, there is no reason to worry about the side effects of EAA supplements. The FDA has determined EAA supplements to be Generally Regarded as Safe (GRAS), while the Food and Nutrition Board of the National Academy of Science has determined that there is no upper limit of consumption beyond which would not be safe.

Amino Acid Infusion: Is There an Advantage Over Oral Ingestion of Amino Acids?

Amino acids can be delivered either by intravenous infusion or oral ingestion. Both routes support protein metabolism in the body, as well as provide amino acids for other purposes. But what are the advantages and disadvantages of each?

The use of amino acid infusions to provide nutritional support to individuals incapable of eating a sufficient amount of dietary protein to meet nutritional requirements dates back to the 1960s. An amino acid infusion can either provide partial nutritional support or may be given as part of total parenteral nutrition (TPN). TPN provides all nutrition, including amino acids, carbohydrate, fat, and vitamin and minerals via intravenous infusion, or amino acid injections. But is there a significant advantage to taking amino acids intravenously over taking amino acids orally as a supplement?

Intravenous Amino Acids and TPN

Intravenous amino acids can provide nutritional therapy for protein metabolism (the breaking down and building up of proteins).

An amino acid infusion contains the amino acids with the greatest protein-stimulating effect. These include the essential amino acids leucine, isoleucine, lysine, valine, phenylalanine, histidine, threonine, methionine, and tryptophan, as well as the nonessential amino acids alanine, arginine, glycine, proline, serine, and tyrosine. These amino acids act as protein-building blocks, encouraging protein synthesis in muscle cells and preventing protein breakdown.

An amino acid injection is the administration of amino acids and other nutrients by way of parenteral nutrition. Parenteral administration utilizes routes outside the gastrointestinal (GI tract), such as intravenous routes. Enteral nutrition, on the other hand, is food or drug administered by way of the GI tract, such as with tube feeding.

Intravenous infusion of amino acids is used for patients who cannot take in food or nutrients through the enteral route (GI Tract). For instance, if gastrointestinal absorption is disrupted by inflammatory disease or obstruction, or if tube feeding is not providing adequate nutritional support.

Aminosyn® II is a popular amino acid injection given by way of peripheral vein or central vein infusion and used as a source of nitrogen in the short-term nutritional therapy of patients with adequate body fat who are unable to sustain oral nutrition. This type of amino acid infusion is also administered to help prevent or reverse negative nitrogen balance in patients who cannot take in nutrients via the enteral route.

Individuals who have had large portions of their intestines removed surgically can live indefinitely on total parenteral nutrition (TPN). A 15% amino acid injection can be administered by use of a central venous catheter or by peripheral vein. This amino acid infusion is coupled with vitamins, trace elements, electrolytes, and energy nutrients to provide the necessary nutritional support for weight maintenance or weight gain. In order for the amino acids from TPN to be adequately absorbed and utilized, energy requirements must be met. Energy is typically provided as a combination of dextrose to support carbohydrate metabolism and an intravenous fat emulsion that offers up essential fatty acids to protect against essential fatty acid deficiency and fulfill the dietary balance of fat and carbs.

TPN using amino acid injections can promote muscle protein synthesis, as well as meet other requirements for amino acids, including immune function and brain neurotransmitter synthesis.

The primary drawback to amino acid infusion as the sole source of amino acids from the physiological perspective is that the intestine atrophies. This is because some of the amino acid requirements of the gut are satisfied by direct uptake of amino acids from the digestion of orally ingested protein or amino acids. Atrophy makes the intestines more permeable to diffusion of bacteria and bacterial products from the gut into the body. Of course, if TPN is used because of the removal of the gut, this point is moot. If the intravenous infusion of amino acids is used alongside orally ingested protein, gut integrity will be maintained so long as the oral intake is sufficient.

Benefits of Amino Acid Infusion

The clinical benefits of amino acid infusion in patients who are incapable of ingesting adequate nutrition orally are well established. In addition, intravenous infusion of amino acids in individuals fully capable of ingesting amino acids orally is gaining popularity. The “selling point” of this therapy is that the exact concentrations of individual amino acids in the blood can be precisely controlled. This is promoted as particularly important to the relative concentrations of amino acid precursors of specific brain neurotransmitters. This approach is used in recovery from addiction, as well as for general support of protein metabolism in the body.

The premise of intravenous amino acid therapy is that the individual cannot get the full benefit from orally ingested amino acids, or that the intravenous infusion somehow confers special beneficial effects.

Advantages of Oral Ingestion of Amino Acids

The oral ingestion of amino acid solutions has advantages over amino acid infusion. There is no risk associated with oral ingestion, whereas intravenous infusion carries with it the risk of vein irritation. A health care provider is needed to perform the intravenous infusion, whereas free amino acids for oral consumption are relatively cheap and readily available.

It is possible to obtain a mixture of essential amino acids for oral consumption specifically designed for a particular condition, such as reaching your ideal body weight, whereas the options for intravenous infusion are much more limited due to the arduous procedure to obtain approval from the FDA.

There are also physiological advantages to the oral ingestion of amino acids over peripheral infusions. Most important of these is that the uptake and utilization of amino acid solutions by the intestines provides a direct source of essential nutrition.

Orally ingested amino acids are directly absorbed by the intestines and require no digestion. The amount of amino acids provided to the body by the two routes (oral and intravenous) are thus similar. Since orally ingested amino acids pass through the intestines, liver, and other organs before reaching the peripheral circulation, the peripheral plasma concentrations of amino acids reach higher levels when infused intravenously. Conversely, orally ingested amino acids provide more direct support of the internal organs.

Orally ingested and intravenously infused amino acids both stimulate muscle protein synthesis, which is the metabolic basis for muscle growth and strengthening. A clinical study of older individuals showed that muscle protein synthesis was stimulated in response to both intravenously infused as well as orally ingested amino acids. In addition, the profile of amino acid concentrations in the blood reflected the profile of the orally ingested amino acids, so there is no advantage to intravenous infusion in terms of supplying the proper balance of amino acids needed to synthesize neurotransmitters in the brain. Further, a clinical response was observed at dosage levels that are able to be consumed orally without much difficulty.

Side Effects of Amino Acid Injections

Amino acid infusions are now being marketed as a way to boost athletic endurance, protect against muscle loss, and even improve the health of the central nervous system. While amino acid solutions can indeed impart these benefits, amino acid injections were not originally developed for healthy individuals tackling body weight goals. Oral amino acid supplements, however, can help build muscle, sharpen cognitive function, and enhance athletic endurance, and there are no needles or doctors involved. It’s as easy as mixing an amino acid powder with water.

One of the biggest advantages of taking an oral amino acid supplement over an amino acid injection is that no special care is needed and there are no side effects to contend with.

Amino acid injections can cause the following adverse reactions:

  • Inflammation/redness at the injection site
  • Irritation
  • Nausea
  • Flushing
  • Fever
  • Allergic reactions
  • Weight gain
  • Jaundice
  • Urine changes
  • Weakness

Contraindications for amino acid injections are indicated for individuals in hepatic coma, with hepatic insufficiency, severely impaired kidney function or renal failure, or suffering from metabolic disorders due to compromised nitrogen utilization or hypersensitivity to one or more amino acids.

The Verdict

Amino acids can be delivered either by intravenous infusion or oral ingestion of amino acid solutions. Both routes support protein metabolism in the body, as well as provide amino acids for other purposes.

The intravenous infusion procedure has risks and costs that are avoided by oral ingestion, and the amino acid profiles in available intravenous infusion mixtures are limited. For these reasons, amino acid infusion should be used only in individuals who are incapable of ingesting amino acids or who have a limited capacity for absorption. Oral ingestion is the preferred route of delivery of amino acids in most circumstances.

What You Should Know About Lysine Supplementation

Lysine is an essential amino acid required for protein synthesis, collagen development, proper cell function, and tissue repair. But your body cannot make it on its own. You have to get it from the foods you eat or the supplements you take. Lysine supplementation, however, comes with its own set of best practices.

L-lysine, the form of lysine used by the body—usually referred to as simply lysine—is one of nine essential amino acids. This indispensable amino acid is required for protein synthesis, collagen development, proper cell function, and tissue repair. But like the other essential amino acids, your body can’t make it on its own. You have to get it from the foods you eat or the supplements you take. If you’re interested in lysine supplementation, however, you should know that it comes with its own set of best practices.

But before we get into those, let’s first talk about lysine deficiency and what may lead to a lysine-deficient diet.

Lysine Deficiency

In developed countries, such as the United States, lysine is an abundant nutrient in the majority of people’s diets, where it can be found in a variety of food sources, including:

  • Meat
  • Poultry
  • Fish (especially cod and sardines)
  • Cheese (especially Parmesan)
  • Soy products
  • Spirulina
  • Fenugreek
  • Legumes
  • Nuts

However, in poor countries, where cereals are relied upon heavily for nutrition, lysine is the most limiting amino acid.

What is a limiting amino acid, you ask?

Amino acids are known as the building blocks of protein, as they create all the different proteins in our bodies by linking together in long chains. However, if any single essential amino acid is in short supply, protein synthesis will stop as soon as its supply is exhausted. The amino acid in shortest supply during protein synthesis is therefore known as the limiting amino acid.

Because the majority of cereal grains are lysine deficient, lysine becomes the limiting amino acid. And the people who rely on these grains as their main source of food are deficient in this essential amino acid as well.

Based on animal studies, every cereal grain that’s been studied contains an insufficient amount of lysine. Lysine is also the most limiting amino acid in pig feed and falls just behind methionine as the second most limiting amino acid in avian diets.

In fact, over 90% of the lysine produced is used to supplement animal diets. In 2005, 200,000 metric tons of lysine was used in the United States alone to supplement animal feed.

Why do I mention this in an article about lysine supplementation presumably aimed at humans?

It’s merely to make the point that lysine is most likely the most studied amino acid in animal nutrition, yet has received far less attention for its role in human nutrition.

Still, let’s explore what we know thus far.

What Are the Symptoms of Lysine Deficiency?

Symptoms of a lysine deficiency may include:

  • Loss of appetite
  • Mood changes
  • Broken skin
  • Fragile nails
  • Dizziness
  • Fatigue
  • Anemia
  • Hair loss

While lysine is supplied by many animal proteins (meat, fish, poultry, eggs, and dairy products), it’s typically the limiting amino acid in plant proteins. Therefore, vegetarians, and especially vegans, must be diligent in choosing appropriate proteins or taking an essential amino acid supplement to ensure adequate lysine intake.

Lysine supplementation

Lysine and Muscle Protein

Lysine is an important component of muscle tissue. In fact, it’s the second most abundant essential amino acid in human muscle protein.

Even so, lysine does not play a significant role in either molecular signaling (the communication between cells) or protein synthesis (the process of building new proteins) and is only effective in stimulating the synthesis of new muscle protein when it’s included in a mixture of all the other essential amino acids.

Muscle protein is comprised of 20 different amino acids, 9 of which are essential amino acids. However, to build new muscle protein, each of these amino acids must be available to muscle cells in a proportion that roughly matches their own individual contribution to the muscle protein amino acid profile. Lysine, however, is a bit of an outlier.

For maximal effectiveness in stimulating muscle protein synthesis, an essential amino acid formulation must contain more lysine than the amount of lysine found in muscle protein. This is because some dietary lysine may be altered during digestion, rendering it useless.

Also, once lysine is in the blood, it’s transported into muscle tissue very slowly. Therefore, it’s necessary to consume higher levels of lysine to achieve an optimal balance of essential amino acids inside muscle cells.

Lysine and the Immune System

In addition to its important role as a component of muscle protein, lysine is a key player in the immune system. For example, lysine is involved in the development of antibodies and has important antiviral properties.

As a nutritional supplement, lysine has also been found to be active against certain viruses, including herpes simplex viruses.

In fact, a study published in the journal Dermatologica found that a treatment group given L-lysine monohydrochloride (1,000 milligrams 3 times a day for 6 months) had an average of 2.4 fewer infections, and their symptoms were significantly less severe and healing time significantly reduced.

The important role of lysine in immunity to infections is particularly evident when the diet is deficient in this essential amino acid.

A diet deficient in lysine not only impairs immune function but also increases the susceptibility of both animals and humans to infectious disease. Therefore, people whose diets are especially deficient in good sources of lysine, especially vegans and those from countries that rely on cereal grains, would benefit from lysine supplementation.

Those with diets that are deficient in either protein sources or amino acids in general also need to be aware of the possibility of impaired immune function. However, for these people, care must be taken when supplementing with any individual amino acid—including lysine—to support immune function.

The reason for this is that the various amino acids involved in immune function are intricately related. Of the immune system’s major amino acid players, arginine, glutamine, and cysteine are considered the most crucial for proper immune function. But lysine competes with them for transport.

In other words, an excess of lysine relative to other key amino acids may actually impair immune function. Maintaining a normal balance of amino acids in the blood is therefore critical for optimal immune system function.

Lysine and the Maillard Reaction

When you think about the amount of lysine you’re getting in your diet, you need to be aware of one other caveat: the Maillard reaction.

The Maillard reaction refers to a chemical reaction that takes place between amino acids and sugars. In fact, it’s the process that gives browned food its complex flavor (think dark coffee, toasted bread, and charred meat).

Most protein foods that have been processed in a factory are heat treated. This facilitates the formation of Maillard reactions, and these reactions are accelerated at higher temperatures.

Lysine is particularly susceptible to Maillard reactions because it possesses a reactive amino group (every amino acid is made up of one amino group and one carboxyl group) at the end of its side chain (the shorter chain of atoms attached to the main chain, or backbone, of the molecule).

Maillard products can make lysine nutritionally unavailable. By contrast, free lysine (lysine that isn’t bound to other amino acids in a protein string), either alone or in a balanced essential amino acid formulation, is not subject to Maillard reactions.

Additional Benefits of Lysine Supplementation

In addition to the benefits mentioned above, a variety of other health benefits have been attributed to lysine.

Cancer Treatment

In one study, researchers found that a combination of lysine, proline, green tea extract, and vitamin C displayed an anti-tumor effect against pancreatic cancer cells.

Reduced Anxiety

Another study found that lysine was effective in reducing stress-induced anxiety and its associated diarrhea.

Improved Bone Health

Lysine supplementation was found in one study to improve intestinal calcium absorption. Studies have also found that taking lysine and L-arginine together can make bone-building cells more active and increase the production of collagen.

Lysine also works in conjunction with vitamin D to help support the assimilation of calcium and strengthen bones. For those suffering from osteoporosis, higher amounts of calcium in the body may improve bone strength and help prevent fractures.

Reduced Complications from Type 2 Diabetes

In a study of the effects of lysine on insulin and glucagon concentrations, researchers discovered that relatively high doses of lysine supplementation resulted in a small decrease in blood sugar levels and an increase in glucagon and insulin concentrations.

Another study also found that supplementation with lysine was helpful in decreasing infection risk in diabetic patients.

Improved Cardiovascular Health

Additional studies have found that, in combination with vitamin C, lysine helps form the collagen necessary to maintain artery wall strength and help prevent atherosclerosis.

Reduced Gastrointestinal Inflammation

In one study, it was found that lysine has an anti-inflammatory effect on the gut lining, which could have implications for inflammatory diseases of the gastrointestinal tract.

However, before we can definitively say that lysine is beneficial in these areas, additional controlled clinical trials will need to be performed.

Side Effects of Lysine Supplementation

While the use of lysine supplements is generally considered safe and adverse effects are uncommon, lysine has been known to cause stomach pain and diarrhea in some individuals.

There has also been one report of kidney disease linked to lysine supplements, so if you have kidney disease or are taking aminoglycoside antibiotics, please speak with your health care provider before taking lysine supplements.

In addition, lysine supplementation has not been thoroughly studied in pregnant and nursing women, so its use cannot be recommended in this population.

In conclusion, I’d like to leave you with these parting thoughts. While the research on lysine remains spotty, we can say that lysine supplementation is appropriate for individuals whose diets are specifically deficient in this amino acid.

For most other circumstances, a more balanced formulation of essential amino acids is optimal. However, as we stated earlier, because of lysine’s incomplete digestion and slow transport into muscle cells, one should look for a formula containing at least 20% lysine.

Leucine Muscle Building and Performance: The Magic Bullet?

Leucine has received special attention for its role in muscle building, not only because it is the most abundant EAA in muscle protein, but also because of its nutraceutical role as a regulator of muscle protein synthesis. Is leucine the “magic bullet” of muscle building?

Leucine is one of the nine essential amino acids (EAAs). EAAs are considered “essential” because the body can’t make them, and they must be consumed as part of the diet. Among the EAAs, leucine has received special attention for its role in muscle building, not only because it’s the most abundant EAA in muscle protein, but also because of its nutraceutical role as a regulator of muscle protein synthesis—the process of muscle building. But are these leucine muscle building benefits the “magic bullet,” or is leucine no more or less important than any of the other EAAs? The truth is that it falls somewhere in between.

What Is Leucine?

Leucine is one of the three branched-chain amino acids (BCAAs), the other two being isoleucine and valine. The term branched-chain refers to the chemical structure of these EAAs, which consists of branched side chains—the shorter chains of atoms attached to the main chain, or backbone, of the molecule.

Leucine is the best known of the BCAAs and is, as already mentioned, the most abundant EAA in muscle tissue. In addition, leucine acts as a signal to activate various cellular functions, including the process of protein synthesis.

How Muscle Protein Synthesis Works

Muscle protein is in a constant state of turnover, being continuously broken down and resynthesized. Muscle building takes place when the rate of muscle protein synthesis exceeds the rate of muscle protein breakdown. This can occur when there’s a stimulated rate of muscle protein synthesis, a suppression of muscle protein breakdown, or a combination of the two.

The process of muscle protein synthesis itself involves the hooking together of a series of amino acids in a very specific sequence and amount. Under normal conditions, most of the amino acids that hook together to form new muscle protein are those released during protein breakdown.

However, about 15% to 20% of the amino acids released during protein breakdown are not available to build new muscle protein. Some are irreversibly oxidized, while others are released into the bloodstream and taken up by other tissues and organs. For this reason, an additional source of amino acids is needed so that the rate of protein synthesis can catch up with, or exceed, the rate of protein breakdown.

Eleven of the amino acids in body protein are nonessential, which means the body produces them on its own to meet the demands of protein synthesis rates. By contrast, EAAs such as leucine must be consumed in the diet since they can’t be produced in the body. For this reason, consuming sufficient EAAs is mandatory for increasing the rate of muscle protein synthesis.

Leucine Muscle Building Supplements

Muscle protein can’t be built with leucine alone. In fact, for new muscle protein to be produced, all of the EAAs must be available in proportion to their respective contributions to the composition of that protein.

Since leucine is the most abundant EAA in muscle protein, comprising about 23% of the total EAAs, high leucine intake is essential for the production of muscle protein. Consequently, the profile of EAAs consumed for the purpose of stimulating muscle protein synthesis—whether in a natural protein food source or an amino acid supplement—must contain a relatively high proportion of leucine.

There’s no debate about the importance of leucine as a building block of muscle protein. Neither is there any controversy regarding the need for leucine to make up at least 20% to 25% of consumed EAAs to maximally stimulate muscle protein synthesis.

The question is, rather, whether the effects of leucine are so unique that this one substance should constitute a disproportionately greater amount of a dietary amino acid supplement compared with the other EAAs. In other words, is leucine supplementation alone beneficial for building muscle?

Keep in mind that this question is relevant only to amino acid supplements, as there is no natural protein source made up of more than 23% leucine, and there is no natural protein source that contains only leucine. So, in order to answer this, we must first understand leucine’s role as a nutraceutical.

Leucine has been called a nutraceutical because it has the ability to stimulate muscle protein synthesis on its own and is more than just one of the components of muscle protein. In fact, leucine can actually initiate the process of protein synthesis by activating a group of intracellular compounds known collectively as initiation factors.

The key initiation factor activated by leucine is a protein called mammalian target of rapamycin (mTOR), which acts as a sensor within the cell. When leucine concentrations are low, mTOR receives the signal that there’s not enough dietary protein present to build new skeletal muscle protein and is deactivated. But when the concentration of leucine within the cell increases, mTOR is activated.

Activation of mTOR can increase the amount of muscle protein produced, provided there are enough of the other EAAs (in addition to leucine) available to make complete proteins.

Muscle Protein Synthesis and mTOR

In normal, healthy adults, mTOR can be activated and muscle protein synthesis stimulated with a balanced EAA supplement, so there’s no need for extra leucine. However, in many clinical states, muscle protein synthesis is just not as responsive when EAAs are consumed, either as food or as supplements.

When this happens, it’s referred to as anabolic resistance—the reduced stimulation of muscle protein synthesis in response to protein intake. Anabolic resistance often occurs alongside conditions such as cancer or severe trauma or illness or during the regular process of aging.

During a state of anabolic resistance, an EAA supplement containing a disproportionately high amount of leucine (35% to 40%) may be needed to activate mTOR and overcome the resistance.

My team and I actually discovered this in 2006, when we studied the beneficial effects of an EAA mixture with leucine on muscle protein metabolism in elderly and young individuals. You can read about the study, published in the American Journal of Physiology, Endocrinology, and Metabolism, here.

But leucine is not the only way to activate mTOR. Resistance exercise can also further elevate mTOR, providing the potential for increased muscle protein synthesis. However, when engaged in resistance training, sufficient EAAs must be available for the further activation of mTOR to translate into increased protein synthesis.

Put simply, you can’t make something out of nothing. And that’s because a shortage of even one EAA will limit the stimulation of muscle protein synthesis, even after a heavy resistance workout. So while mTOR activation isn’t always linked to increased protein synthesis, it is an anabolic signal when all the necessary components are present.

Leucine Alone Isn’t Enough

The best way to envision the role of leucine in protein synthesis is to think of the EAAs as a football team, where leucine is the quarterback and the other positions are filled with other EAAs, each with their own specific role. Just as a team of only quarterbacks wouldn’t have much success in a game, a nutritional supplement wouldn’t have much success if it contained only leucine.

There have been a number of studies examining the effectiveness of leucine as a nutritional supplement. And as predicted by the analogy above, leucine alone has been shown to have little effect on muscle building—according to a 2011 study published in the Journal of Nutrition.

Compare these findings with a study we published in the journal Clinical Nutrition that showed how a formulation of EAAs with a high proportion of leucine (35% to 40%) helped overcome anabolic resistance and improve muscle mass, strength, and physical function in the elderly.

Leucine is important, but it can’t do the job alone!

Leucine and Muscle Protein Breakdown

The role of leucine in stimulating muscle protein synthesis has been studied extensively, but the building of muscle is determined not only by the rate of protein synthesis but also by the balance between the rates of synthesis and breakdown.

With this in mind, it’s interesting to note that leucine also has the ability to reduce the rate of muscle protein breakdown and, thus, muscle loss. One reason for this is that leucine can stimulate the release of the hormone insulin, and the suppression of muscle protein breakdown by insulin is well known.

As one of the BCAAs, leucine can also suppress protein breakdown directly. However, suppressing muscle protein breakdown only helps build new muscle if the rate of muscle protein synthesis is greater than the rate of breakdown, and this may not occur when consuming just leucine or BCAAs.

In fact, a reduction in muscle protein breakdown caused by leucine or BCAAs alone is accompanied by a corresponding reduction in the rate of muscle protein synthesis. This reflects the fact that the major source of EAAs for building new muscle protein is the EAAs that are released by protein breakdown. Therefore, if muscle protein breakdown is suppressed, the availability of EAAs for protein synthesis is also reduced.

As in the case of muscle protein synthesis, leucine can play a potentially important role in building muscle by inhibiting the rate of muscle protein breakdown, but to increase the anabolic response—meaning synthesis is greater than breakdown—all the EAAs must be consumed.

Leucine and Performance

Leucine is oxidized at an increased rate during endurance sports. This is evidenced in a study published in the Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology. Although a large portion of total energy production isn’t derived from leucine oxidation during exercise, the amount of leucine oxidized is significant in terms of the amount available for incorporation into protein.

In other words, the increased oxidation of leucine during exercise can make its availability—or lack thereof—limiting for the production of new muscle protein.

This is why it’s necessary to consume EAAs in general, and leucine in particular, post exercise. Consuming protein shakes, whey protein, or EAAs after exercise will not only prevent the loss in muscle protein that would occur otherwise (because of the oxidation of leucine) but will also increase muscle protein synthesis and increase muscle strength and function.

Leucine and Type 2 Diabetes

We’ve known for 50 years that blood concentrations of leucine (and the other BCAAs) are elevated in individuals with type 2 diabetes. This knowledge has spurred theories that the BCAAs, and leucine in particular, are somehow involved in the development of insulin resistance and, ultimately, type 2 diabetes.

A recently proposed theory that’s been gaining popularity is based on the premise that the activation of mTOR may be involved in causing insulin resistance. However, this theory is contradicted by studies that have shown that increasing leucine concentrations in dietary supplements not only doesn’t cause insulin resistance but may also, in some circumstances, actually improve blood sugar control.

Studies have also shown that supplementing with all the BCAAs can improve insulin sensitivity in a variety of insulin-resistant states.

Additional Benefits of Leucine

Leucine serves other functions as well. For example, it:

  • Increases the number of muscle mitochondria—the organelles where adenosine triphosphate (ATP) is generated to fuel muscle contraction during exercise
  • Promotes the growth and repair of bone tissue
  • Stimulates growth hormone production
  • Speeds wound healing

Perhaps the most important takeaway here is that leucine—like most things in life—can’t do what it does alone. It needs the help of all the EAAs to be the magic bullet of muscle building the body needs.

Is leucine the “magic bullet” of muscle building?

Should You Take a Glutamine Supplement?

Glutamine supplements have become popular for boosting glutamine levels in the body, especially among people looking to build muscle mass. But should you take a glutamine supplement? Let’s find out!

Glutamine, also known as L-glutamine (the form used by the body), is one of the most well-known amino acids in the supplement world because of the many roles it plays in the body. It’s an important building block of protein, it nurtures digestive tract health, and your immune system depends on it. While glutamine is produced naturally in the body and is found in various foods, glutamine supplements have become popular—especially among people looking to build muscle mass—for boosting glutamine levels. But should you take a glutamine supplement? Is it worth it? Let’s find out!

Glutamine’s Main Role in Muscle

Glutamine is the most abundant free amino acid in skeletal muscle and is required for muscle protein synthesis (the building of new muscle tissue). And because it’s made in the body and is available in large amounts, there’s never a shortage of glutamine for protein synthesis.

Glutamine’s main role in muscle is detoxifying the ammonia that’s released when amino acids are metabolized. In fact, glutamine is the main carrier of ammonia throughout the body.

When ammonia is released during the metabolism of certain amino acids, including the branched-chain amino acids isoleucine, leucine, and valine, it’s transferred to the amino acid glutamate to form glutamine in muscle. Glutamine is then released by muscle and carried via the blood to the liver, where the toxic ammonia is converted into nontoxic urea and excreted in the urine.

Muscle Glutamine and Critical Illness

Depletion of muscle glutamine occurs in almost all diseases and illnesses. This is because these conditions are widely known to lead to muscle wasting, and glutamine depletion occurs at the same time as the net breakdown of muscle.

It has therefore been widely postulated that glutamine depletion resulting from impaired production causes muscle protein breakdown and, thus, the wasting away of muscle. However, this is not the case in critically ill patients. In fact, glutamine synthesis in muscle is accelerated in critically ill patients.

The reduction in glutamine concentration in muscle actually results from the rapid transport of glutamine out of the muscle and into the blood, where it’s taken up at increased rates in other tissues and organs. Because of this rapid use by other tissues and organs, the blood level of glutamine drops despite its accelerated release from muscle.

Accelerated glutamine production in muscle occurring at the same time as an increase in muscle protein breakdown is to be expected. As mentioned earlier, the reason for this is that when muscle protein breaks down, amino acids are released and metabolized, creating potentially toxic ammonia in the process.

In other words, if you speed up protein breakdown, you create a greater need for the resulting ammonia to be cleared away from the muscle and transferred to the liver so it can be converted into urea and eventually excreted in the urine. Urea excretion is increased in almost all forms of serious illness. And as we’ve already discussed, glutamine plays a key role in this process.

Thus, the concentration of glutamine in muscle falls because it’s being rapidly exported into the blood to deal with increased ammonia concentrations.

Muscle Glutamine and Overtraining Syndrome

Overtraining syndrome is a condition that occurs when a person doesn’t allow themselves sufficient time to recover from workouts. Though individual symptoms vary, the main symptom seen is a deterioration in exercise performance despite harder and harder training.

Although there’s little doubt that overtraining does, in fact, occur, the exact basis for the syndrome is still uncertain. Likewise, even though reduced concentrations of glutamine in muscle and blood are markers of overtraining syndrome, it’s unclear if decreases in glutamine actually cause the syndrome or if glutamine depletion is merely a symptom of it.

Supplementing with Glutamine During Critical Illness and Overtraining Syndrome

The relationship between decreases in muscle glutamine concentration and net loss of muscle protein (in critical illness) and deterioration of performance (in overtraining syndrome) seems to lead logically to the use of glutamine supplements. However, there’s little evidence that glutamine supplements maintain muscle mass and function, regardless of the situation.

How can this be?

For one thing, the body normally makes about 80 grams of glutamine per day, and the rate of glutamine production increases in pathological states. In addition, glutamine makes up a substantial percentage of dietary protein, so daily consumption of glutamine may be as much as 80 grams per day as well.

Therefore, it’s very difficult to consume enough glutamine in supplement form to make a significant impact on the body’s glutamine levels relative to the amount that’s normally produced and consumed through your normal diet.

Moreover, as we alluded to earlier, it’s very difficult to get glutamine into muscle cells when the process of muscle breakdown signals the body to release more glutamine into the blood to deal with increased levels of ammonia.

Glutamine doesn’t move freely into and out of muscle. Rather, it has a specific transporter that shepherds it from the blood to the cell against a concentration gradient—an area of higher concentration to one of lower concentration.

But that transport mechanism is reversed in critical illness and overtraining syndrome, so rather than carrying glutamine into the muscle, it’s carrying it out of the muscle and into the blood. As a result, very little glutamine will enter the muscle even when the blood concentration is increased significantly with glutamine supplementation.

Consequently, taking L-glutamine supplements has little impact on muscle mass or function.

Glutamine and Immune Function

Immune function involves a complex network of immune cells and signaling molecules that are crucial for fighting infection. A variety of immune system functions are supported by glutamine metabolism, and the decrease in blood glutamine concentration in critical illness discussed earlier occurs in part because of the accelerated use of glutamine by the immune system.

In a review of 14 different clinical trials of glutamine supplementation, researchers analyzed the ability of a glutamine supplement to enhance immune function, as reflected by infectious complications and length of hospital stay in surgical or critically ill patients. The analysis showed that there may be an association between glutamine supplementation and a reduction in infectious complications and shorter hospital stays, although the association was not very strong.

The importance of immune function in hospitalized patients is plainly evident, as resistance to infection is crucial to the recovery process. However, what’s less well appreciated is that strenuous exercise also stresses the immune system.

In fact, according to a study published in the journal Nutrition, glutamine supplementation may decrease the incidence of infections in endurance athletes following bouts of intense exercise.

Glutamine and Intestinal Health

In addition to the role played by the intestines in digestion and nutrient absorption, intestinal cells are also involved in a variety of other functions, including immune response and hormone secretion.

Amino acids, particularly glutamine and other nonessential amino acids, which can be produced in the body, play an important metabolic role in the intestines.

Glutamine metabolism is a crucial component of energy generation in the intestines and is a precursor for a number of important metabolic pathways, especially those leading to the production of the amino acids ornithine, citrulline, proline, and arginine.

Because of the specific metabolic function of glutamine in the intestines as well as its protective action, including its role in modulating intestinal permeability, many clinical trials have been conducted to assess the benefits of supplementation on intestinal health, particularly with respect to states in which normal intestinal function is disrupted—such as ulcerative colitis, Crohn’s disease, and leaky gut syndrome.

However, the results of these trials have been confusing and inconclusive. This is in part due to the fact that the amino acids glutamate and proline can easily substitute for many of the metabolic roles of glutamine, including energy production and amino acid synthesis.

So does glutamine supplementation benefit gut health? I’m afraid the answer to that question is, at best, a firm maybe.

Glutamine and Neurotransmitters

Glutamine plays several parts in the brain and central nervous system (CNS). Its principal action is as a precursor in the production of glutamate and aspartate, both of which are excitatory neurotransmitters. Glutamine is also the precursor of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA).

Much of the production of glutamate and GABA from glutamine occurs via a metabolic pathway within the CNS. Initially, glutamine is produced from glutamate and ammonia in specialized cells within the CNS called astrocytes, which are star-shaped glial cells—cells that surround and support the work of neurons. Newly produced glutamine is then transferred to neurons, where it’s converted into glutamate and GABA and sometimes aspartate.

The relationship between glutamine and glutamate in the astrocyte is cyclic. Glutamine metabolism forms glutamate, which in turn combines with ammonia to reform glutamine. For this reason, this process is referred to as the glutamine-glutamate cycle.

As stated earlier, the glutamate, GABA, and aspartate produced from glutamine act as neurotransmitters. And since glutamate and aspartate work to counteract the influence of GABA, the balance of these neurotransmitters is crucial for healthy brain activity.

Thus, the metabolic reactions that regulate the glutamine-glutamate cycle are tightly controlled to ensure that the appropriate balance of neurotransmitters is maintained.

Glutamine Supplementation and Brain Function

Glutamine has the ability to pass through the blood-brain barrier via a specialized transporter, so in theory, glutamine ingestion can increase levels of glutamine in the brain. But most of the glutamine in the brain comes from the process of glutamate combining with ammonia in the brain’s astrocytes.

In spite of this, glutamine supplementation is often recommended for improving brain health, particularly when blood levels of glutamine are low. However, evidence to support this claim is minimal.

In fact, it’s very difficult to increase concentrations of glutamine in the blood and ensure it enters the brain because a typical glutamine supplement provides only a small fraction of the total amount of glutamine present in the body. In addition, the body regulates the entry of glutamine into the brain to maintain a proper balance of glutamate, aspartate, and GABA.

The primary source of glutamine in the brain is also derived from the glutamine-glutamate cycle, rather than the blood, so the failure to demonstrate a beneficial effect of glutamine on brain health—even with amounts greater than what’s normally consumed in the diet—is not surprising.

So…Should You Take a Glutamine Supplement?

Glutamine is the most abundant amino acid in the body and plays many metabolic roles. It serves as a shuttle for transferring ammonia from muscle to liver, fuel source for the intestines and immune system, and precursor for key neurotransmitters in the brain.

Because of glutamine’s many diverse roles, L-glutamine supplements have been promoted extensively, particularly in stressful or pathological situations in which blood glutamine concentrations have been depleted.

While there’s some evidence that glutamine supplementation may aid immune function when blood concentrations of glutamine are decreased, supplementation has shown only minimal benefits in other areas, including muscle building and brain function.

The ambiguous results of glutamine supplementation can in large part be attributed to the rate of glutamine production in the body as well as normal dietary consumption.

As stated earlier, glutamine production in the body is already so great that the incremental increase in availability provided by a dietary supplement—even in high doses—will usually be of only minimal significance.

should you take a glutamine supplement?

What’s with HMB Supplements?

HMB has been shown to promote muscle gain in individuals who are working out. However, this muscle-promoting effect is dependent on adequate availability of essential amino acids (EAAs). HMB supplements without the support of EAAs just don’t cut it.

From hydroxymethylbutyrate to beta-hydroxy-beta-methylbutyrate (or β-hydroxy-β-methylbutyrate), HMB—a chemical produced when the body breaks down the amino acid leucine—is known by a variety of names. But what exactly are HMB supplements?

HMB supplements are promoted as nutritional substances that can help speed wound healing and support individuals with muscle-wasting diseases such as cancer and HIV. Proponents also tout HMB supplements (or HMB in combination with creatine monohydrate) as a way to slow the muscle wasting that comes with aging.

To be fair, research does support the presence of some beneficial effects of HMB. For example, it’s been shown to promote muscle growth in individuals who work out. However, it should also be noted that this muscle-promoting effect is dependent on the adequate availability of essential amino acids (EAAs).

In other words, HMB supplements in isolation, without the support of EAAs, have a minimal effect on muscle building.

How Does HMB Work?

HMB and the EAA leucine are closely linked, and it’s necessary to understand the relationship between them to understand how HMB works.

Leucine is the most abundant of the nine EAAs found in muscle protein. It also acts as a nutraceutical aid in turning on the body’s muscle-building switch. In fact, it’s one of the three branched-chain amino acids—the others being isoleucine and valine—that make up about a third of muscle protein. Some experts also propose that leucine turns on the process of protein synthesis (muscle building) via the action of HMB.

HMB is a metabolite of leucine, meaning it’s derived from the breakdown of leucine. In a series of step-by-step reactions, about 15% of the leucine present in blood is also irreversibly broken down to ammonia and carbon dioxide. This sequence of reactions by which leucine is reduced to its basic components is called a metabolic pathway.

But there’s more than one metabolic pathway involved in the breakdown of leucine. And it’s actually via a minor pathway that the leucine metabolite HMB is produced, yet it’s still proposed to be the active component of leucine. However, as leucine is being broken down by the body, only about 5% of it is broken down via the pathway that results in HMB.

Combine this with the fact that only 15% of leucine is broken down at any given time, and it’s clear that the amount of HMB produced by leucine breakdown makes up only a very small percentage of available leucine.

As a result, the concentration of HMB in body fluids is far less than that of leucine. And since results with dietary supplementation aren’t achieved unless the concentration of HMB is increased many times above the normal physiological level, it’s unlikely that leucine’s effects on muscle protein synthesis are, in fact, mediated by HMB.

However, when the availability of HMB is increased using dietary supplements, it seems to work as a nutraceutical in the same way leucine does in that it activates the molecular mechanisms involved in the initiation of protein synthesis.

Specifically, the increase in HMB concentration supplied by supplementation activates a molecule known as mammalian target of rapamycin, or mTOR.

The molecule mTOR plays a key role in controlling the initiation of protein synthesis. When mTOR is activated, a series of additional chemicals involved in the initiation of protein synthesis is activated as well. And when all of these molecules are switched on, the process of protein synthesis begins. Likewise, when mTOR is activated by excess levels of HMB, the process of protein synthesis is also stimulated.

A sustained increase in muscle protein synthesis should ultimately be reflected by an increase in muscle strength, function, and mass over time. However, the use of HMB alone does not result in an increase in protein synthesis.

In fact, any increase in protein synthesis resulting from HMB supplements will last only as long as there’s an adequate supply of EAAs. And once there’s a dip in the EAA supply, the effect of HMB stops as well.

HMB Needs EAAs to Work

If you activate mTOR but your body doesn’t have enough EAAs circulating in the bloodstream, then muscle protein synthesis will only be increased to a limited extent.

As stated earlier, muscle protein contains nine EAAs, each of them unique and each a vital component of newly produced proteins. Unlike the 11 nonessential amino acids, EAAs can’t be produced in the body and have to be obtained through dietary sources.

However, if you aren’t getting enough EAAs through protein-rich foods or EAA supplements, then your only source of EAAs is the protein already present in your body.

In this case, your body begins to break down its protein stores and release the component amino acids, including EAAs, for use by the cells of the body. However, under normal conditions, only about 85% of amino acids released in this manner are reincorporated into protein; the rest are lost to oxidation.

But let’s circle back to HMB.

To be effective on its own, HMB must increase the efficiency of EAA reutilization for protein synthesis. However, as we just indicated, that process is already 85% efficient, which means there’s a definite limit as to how much more efficient the recycling of EAAs back into protein can be.

Therefore, it becomes clear that dietary supplementation with HMB works only when there’s an excess amount of EAAs available. And an excess supply of EAAs can occur via only two mechanisms:

  • EAAs must be consumed at the same time as HMB
  • The rate of protein breakdown must be accelerated

However, an increase in protein breakdown would only undermine the beneficial effect of an increase in protein synthesis, as protein gain is the result of the balance between protein synthesis and breakdown. Thus, supplemental doses of HMB can only result in a sustained increase in the net gain of muscle protein if consumed at the same time as an abundant supply of EAAs.

Benefits of HMB Supplements

All this being said, there are still a few conditions—such as catabolic states involving rapid muscle loss—that may benefit from HMB supplementation. This is because protein breaks down much more rapidly in catabolic states such as critical illness or HIV.

This protein breakdown provides extra EAAs that would, under normal conditions, be oxidized. In these situations of increased EAA availability that occur during catabolic states, the anti-catabolic action of HMB may help maintain muscle mass and function and decrease the rate of muscle protein breakdown.

However, recommendations for catabolic states generally specify that HMB should be included as part of a multifaceted approach for muscle maintenance that also incorporates resistance training and a high-protein diet for EAA maintenance.

Exercise also accelerates muscle breakdown (via muscle damage that occurs as a natural part of muscle use) and EAA oxidation. Consequently, the use of supplemental HMB may result in improved performance by improving the reutilization of EAAs released by protein breakdown for the synthesis of new protein.

Is HMB Better Than EAAs Featuring Leucine?

The body’s response to dietary supplementation with HMB alone is similar to that resulting from supplementation with leucine alone.

Just as HMB requires the presence of elevated levels of all the EAAs, so, too, does leucine require the other EAAs to be effective. In addition, the body’s response is more robust when leucine is included as part of a mixture of all the other EAAs than when it (or HMB) is used alone.

Two studies performed in the same laboratory, using the exact same protocol, demonstrate this most clearly. In one experiment, the effectiveness of HMB was assessed, and in the other experiment, the effectiveness of a mixture of EAAs (containing about 40% leucine) was determined.

Both studies investigated how effective HMB and EAA supplements were, compared with a placebo, at diminishing the loss in muscle mass and function that normally occurs with inactivity.

The subjects tested were over the age of 65, and both lean body mass and performance on various physical function tests were measured before and after 10 days of strict bed rest.

In the first study, following 10 days of bed rest, participants were put through a strength training program for a period of 8 weeks. In addition, beginning 5 days prior to bed rest and lasting until the end of the rehabilitation phase, the control group received a placebo powder and the subjects in the experimental group received 1.5 grams of HMB twice daily in its calcium salt form, for a total of 10 weeks of supplementation.

In the second study, participants in the control group received a placebo, while subjects in the experimental group received 15 grams of EAAs 3 times a day throughout the entire 10 days of bed rest. However, in this study, neither group received any weight training.

When comparing the data collected on all the subjects included in these studies, it becomes clear that the major differences between HMB and EAAs can be seen in terms of the tests of physical function—all of which have been validated as representative of the normal physical requirements for activities of daily living in older adults.

While the placebo group had major impairments in all tests of physical function after 10 days of bed rest, those given EAA supplementation—but not HMB supplementation—had significantly improved outcomes.

For example, the time required for subjects to go from a standing position to the floor and back up again (floor transfer test) increased by approximately 40% in the placebo group. Floor transfer rate was also not significantly affected by HMB supplementation. However, the group given EAA supplementation shortened their floor transfer time by 6%.

In another example, the time required to walk up a flight of stairs increased by 18% in the placebo group. HMB once again had no beneficial effect on this response, but those receiving EAA supplementation showed virtually no increase in the amount of time it took them to perform this task.

Finally, the number of toe raises (test of foot flexibility) that could be completed in 1 minute was reduced by almost 80% in both the control group and the HMB supplementation group, whereas the loss of this function with bed rest was completely prevented with EAA supplementation.

These bed rest studies are the only direct comparison that’s been completed of the muscle-building effects and strength gains provided by dietary supplementation with HMB and a formulation of EAAs. Yet the results clearly demonstrate the beneficial effects of EAAs in preventing declines in physical function and fail to demonstrate any beneficial effect of HMB alone.

These results are also consistent with the fact that stimulation of protein synthesis requires the availability of excess amounts of all component amino acids—especially EAAs.

While HMB’s activation of mTOR and other molecules involved in the initiation of protein synthesis may result in a transient increase in muscle protein synthesis, this increase can’t be sustained at a rate sufficient to result in improvements in physical function.

The HMB Takeaway

HMB is widely promoted as a muscle-building molecule that stimulates protein synthesis. While in some cases HMB supplementation may provide benefits, direct comparison with EAA supplementation highlights the fact that any benefit provided by HMB is minimal.

Whatever molecular signaling occurs as a result of HMB supplementation can instead be achieved by taking an EAA supplement that contains leucine. The availability of all EAAs—which are not present in HMB supplements—in excess amounts is required for a sustained increase in protein synthesis, muscle cell growth, and body composition changes that result in greater lean mass versus fat mass.

Furthermore, combining HMB with EAAs would not be expected to be particularly helpful, as the EAAs would elicit the action of HMB on their own.

HMB Supplements

How Essential Amino Acids Can Prevent and Even Reverse Age-Related Muscle Loss

Muscle loss with aging is one of the inescapable characteristics of growing older. While age-related muscle loss is a normal part of the aging process, we can temper its effect with the nutritional support of essential amino acids.

Muscle loss with aging is one of the inescapable characteristics of growing older. While age-related muscle loss is a normal part of the aging process, we can temper its effect with the nutritional support of essential amino acids (EAAs).

It’s Never Too Early to Combat Age-Related Muscle Loss

There’s nothing wrong with embracing the mentality that 40 is the new 20, but don’t fool yourself into believing age is nothing more than a number. Growing older does come with certain physiological changes. Yet there’s no reason your golden years can’t be every bit as vibrant as your youth. And the sooner you acknowledge how the passage of time influences certain biological processes, the better off you’ll be.

As you grow older, age-related muscle loss, which scientists refer to as sarcopenia or age-related sarcopenia, begins to erode your lean muscle mass. This process likely begins earlier than you think. Once you reach the age of 30, you begin to lose between 3% and 8% of your overall muscle mass each decade. The rate of decline increases once you turn 60.

Understanding Anabolic Resistance

Muscle loss with aging occurs because as the years wear on, we lose the ability to make new muscle protein from dietary protein. The impaired ability to build new muscle protein is called anabolic resistance.

When your body enters an anabolic resistant state, it has trouble getting the motor started. The starter for the motor, in this case, is a factor inside the muscle cells called mTOR. mTOR starts the whole process of protein synthesis. The activation of mTOR begins a cascade of responses that ultimately result in the initiation of protein synthesis. Together these responses are called initiation factors.

In aging muscle, the reactivity of mTOR and the other initiation factors is blunted, and this is a basis of anabolic resistance.

The Vicious Cycle of Age-Related Sarcopenia

This ongoing loss of skeletal muscle mass leaves older adults with less control over their bodies. Age-related changes to your muscle tissue and muscle strength don’t just influence your ability to excel during a strength-training workout, they also make you more prone to falls and other types of injuries.

Age-related sarcopenia can kick off a vicious cycle: your muscle strength decreases, which limits your ability to carry out physical activity, which causes further muscle loss. Ultimately, this can result in what health care professionals refer to as frailty, a condition that leaves you extra susceptible to external stressors more hearty individuals would be able to navigate with few to no lasting consequences.

Researchers have identified age-related sarcopenia as the primary factor behind the frailty we associate with aging, such as an increased propensity to fall, compounded by a higher likelihood of suffering an injury such as a broken hip due to a fall and the decreased ability to heal in the aftermath of such an injury.

The more frail you become, the greater the impact of each stressor. As the adverse effects of minor illnesses and injuries accumulate, individuals find it more and more challenging to live independently. Increased frailty also heightens the risk of early death.

Muscle loss with aging is one of the inescapable characteristics of growing older. While age-related muscle loss is a normal part of the aging process, we can temper its effect with the nutritional support of essential amino acids (EAAs). It's Never Too Early to Combat Age-Related Muscle Loss There's nothing wrong with embracing the mentality that 40 is the new 20, but don't fool yourself into believing age is nothing more than a number. Growing older does come with certain physiological changes. Yet there's no reason your golden years can't be every bit as vibrant as your youth. And the sooner you acknowledge how the passage of time influences certain biological processes, the better off you'll be. As you grow older, age-related muscle loss, which scientists refer to as sarcopenia or age-related sarcopenia, begins to erode your lean muscle mass. This process likely begins earlier than you think. Once you reach the age of 30, you begin to lose between 3% and 8% of your overall muscle mass each decade. The rate of decline increases once you turn 60. Understanding Anabolic Resistance Muscle loss with aging occurs because as the years wear on, we lose the ability to make new muscle protein from dietary protein. The impaired ability to build new muscle protein is called anabolic resistance. When your body enters an anabolic resistant state, it has trouble getting the motor started. The starter for the motor, in this case, is a factor inside the muscle cells called mTOR. mTOR starts the whole process of protein synthesis. The activation of mTOR begins a cascade of responses that ultimately result in the initiation of protein synthesis. Together these responses are called initiation factors. In aging muscle, the reactivity of mTOR and the other initiation factors are blunted, and this is a basis of anabolic resistance. The Vicious Cycle of Age-Related Sarcopenia This ongoing loss of skeletal muscle mass leaves older adults with less control over their bodies. Age-related changes to your muscle tissue and muscle strength don't just influence your ability to excel during a strength-training workout, they also make you more prone to falls and other types of injuries. Age-related sarcopenia can kick off a vicious cycle: your muscle strength decreases, which limits your ability to carry out physical activity, which causes further muscle loss. Ultimately, this can result in what health care professionals refer to as frailty, a condition that leaves you extra-susceptible to external stressors more hearty individuals would be able to navigate with few to no lasting consequences. Researchers have identified age-related sarcopenia as the primary factor behind the frailty we associate with aging, such as an increased propensity to fall, compounded by a higher likelihood of suffering an injury such as a broken hip due to a fall and the decreased ability to heal in the aftermath of such an injury. The more frail you become, the greater the impact of each stressor. As the adverse effects of minor illnesses and injuries accumulate, individuals find it more and more challenging to live independently. Increased frailty also heightens the risk of early death. [infographic] How Muscle Loss Creates a Downward Spiral As your muscle strength decreases, it becomes more difficult to be physically active. This results in more lost muscle mass and strength, which can culminate in what health care professionals refer to as frailty. Frailty makes you more susceptible to stressors like illness and injury. The more frail you are, the greater the damage done by each subsequent stressor. Ultimately, it becomes more and more difficult for frail individuals to live on their own. Becoming increasingly frail also raises your risk of early death. [/infographic] While that all sounds grim, you have the ability to preserve—and even increase—your muscle mass as you grow older. Physical activity such as resistance exercise inarguably plays a vital role in preserving muscle mass as you age; however, nutrition will have just as strong—if not an even stronger—influence on your ability to preserve and build muscle. Optimizing Your Nutrient Intake to Combat Muscle Loss As you may be aware, when it comes to providing your muscle fibers with the optimized nutrition they need to maintain themselves and grow, protein is the macronutrient to prioritize. When you don't provide your body with enough protein, your body will lose the ability to keep up muscle mass and bone density. Determining your ideal protein intake can be challenging. Studies have shown that many factors affect the quantity of protein your body requires on a daily basis, such as: Age Gender Physical activity habits Muscle mass to fat ratio Keep in mind, too, that your muscle mass to fat ratio differs from your body mass index (BMI). It's entirely possible to be quite thin and still have high levels of fat compared to lean muscle, which increases the likelihood that you'll develop age-related sarcopenia. According to findings published in Current Opinion in Clinical Nutrition and Metabolic Care, eating between 25 grams and 30 grams of protein with each meal "maximally stimulates muscle protein synthesis in both young and older adults." The authors noted, however, that when elderly subjects consumed protein and carbohydrates together or ate less than 20 grams of protein per meal, that blunted muscle protein synthesis. Choosing the right protein sources will ensure each gram does the most work. When it comes to selecting protein sources, there's one element you should pay the closest attention to: their amino acid content. If you're aging and seeking to combat muscle wasting, you'll benefit the most from increasing your intake of an amino acid called leucine. Why Leucine Matters So Much Leucine, an essential amino acid (EAA) called a branched-chain amino acid (BCAA) because of its chemical structure, is one of the most important dietary regulators of mTOR activity. If the proportion of leucine in an essential amino acid mixture is increased to an amount that exceeds its normal contribution to the composition of dietary protein, that EAA supplement can then effectively activate mTOR in aging muscle. However, leucine alone is not enough. You may have noticed that I did not recommend taking a leucine supplement, but rather an amino acid supplement formulated to contain a higher concentration of leucine. That's because all nine essential amino acids need to be present in the proper proportion to produce new muscle protein. You can think of leucine as the quarterback of a football team—it may be the pivot point of how the team performs, but without the other players the team is not going to have much success. How the Other 8 Essential Amino Acids Contribute When you consume a large amount of the EAA leucine, you increase the rate at which leucine gets broken down since the body is designed to maintain steady levels of EAAs. And since the enzyme that breaks down leucine is also responsible for metabolizing the other two essential BCAAs, valine and isoleucine, they also get broken down at an increased rate. Consequently, the proportions of valine and isoleucine in an EAA formulation containing abundant leucine must also be increased. Lysine is another EAA with distinct characteristics—it is not transported into muscle as readily as other EAAs are. For this reason, the optimal profile of EAAs to maximally stimulate anabolic-resistant muscle includes proportionately more lysine than is reflected in the composition of muscle protein. So, even though it may seem logical to provide EAAs for a muscle-building supplement in a profile similar to the makeup of muscle, adjustments can be made to boost the signal and improve delivery of amino acids to overcome the anabolic resistance that results in muscle loss. The remaining five EAAs—phenylalanine, threonine, methionine, tryptophan, and histidine—also need to be included in a mixture of EAAs to maximally stimulate muscle protein synthesis. In order to include disproportionately high amounts of BCAAs and lysine, however, the proportionate contribution of these additional EAAs must be reduced below what occurs in muscle protein. [infographic] Building an Optimal Essential Amino Acid Blend to Address Age-Related Muscle Loss First and foremost, you'll want high concentrations of leucine, an EAA and BCAA. Leucine activates mTOR in aging muscle, helping to stimulate maintenance and growth. You'll also need all the other EAAs—think of leucine like a quarterback. No matter how skillful that player is, he still needs the rest of his team to win. For the best results, you'll want to increase the proportions of the other two essential BCAAs, valine and isoleucine. You'll also want to up the lysine content. To make room for these adjustments, you'll need to scale back on the amount of phenylalanine, threonine, methionine, tryptophan and histidine you include. [/infographic] The Science Behind How Essential Amino Acids Prevent and Reverse Age-Related Muscle Loss A wealth of research has been conducted on the link between amino acids and age-related declines in protein metabolism, muscle function, muscle growth, and more. The scientists behind one study set out to examine how an amino acid mixture enriched with leucine affected muscle protein metabolism in both young and elderly subjects. They found that ingesting the enriched EAA mixture resolved anabolic resistance in elderly subjects. The mixture of EAAs was 3 times more effective at stimulating muscle protein synthesis in older individuals on a gram-per-gram basis than was whey protein isolate, which is a very high-quality protein by traditional means of assessment. Another study showed that a specifically formulated EAA supplement decreased loss of muscle mass and strength that occurs with bed rest and recovery from hip replacement. This is especially relevant when it comes to preventing muscle loss associated with aging, as older individuals are more likely to experience extended hospitalization and more likely to suffer adverse consequences from the inactivity imposed by hospital stays. Yet another study demonstrated that daily supplementation with EAAs improved muscle mass and function in healthy, active elderly women. The authors wanted to determine whether essential amino acid supplementation improves post-absorptive muscle protein fractional synthesis rate, lean body mass, muscle strength, and other physiological processes. The randomized, double-blinded, placebo-controlled trial found that ingesting the essential amino acid blend stimulated the muscle protein fractional synthesis rate as well as IGF-1 protein expression. Overall, the authors concluded that EAA supplementation improved lean body mass as well as muscle protein synthesis and that it could be a means of offsetting the "debilitating effects" of age-related sarcopenia. [infographic] 5 Science-Backed Ways EAAs Offset Age-Related Muscle Loss Researchers have shown that an amino acid blend enriched with leucine resolved anabolic resistance in elderly subjects. An essential amino acid blend proved 3 times more effective at stimulating muscle protein synthesis than whey protein isolate. An EAA supplement reduced losses of muscle mass and strength related to bed rest. Daily supplementation with EAAs can improve muscle mass and function. Studies show that EAAs can improve lean body mass and muscle protein synthesis, making them a possible means of treating age-related sarcopenia. [/infographic] Key Takeaways to Help You Remain Healthy and Vital as You Age Experts from across the globe agree that both the loss of muscle mass and the loss of muscle strength are highly prevalent and important risk factors for disability and potential mortality as individuals age. This makes identifying treatments for age-related muscle loss a key priority when it comes not only to improving average life expectancy for older people, but also reducing health care costs and enhancing overall quality of life. Ensuring an optimal protein intake will form a foundational part of any successful strategy for maintaining muscle mass (and bone density!) as you age. The kind of protein you eat will be just as impactful as the amount. Leucine, an EAA and BCAA found in certain protein sources, makes uniquely significant contributions to the muscle maintenance and growth processes within the human body. Consuming amino acid supplements designed to contain higher concentrations of leucine (as well as certain other helper amino acids) can dramatically influence your body's ability to retain and increase lean muscle mass as you age. The difference between the effectiveness of EAAs and intact protein cannot be made up just by consuming more of the intact protein, because the optimal profile of EAAs will never be achieved with intact protein. If you're interested in learning more about the advantages of essential amino acid supplements compared to dietary protein sources, this article is an excellent place to start. And if you'd like a quick takeaway in a nutshell, here it is: when it comes to amino acids for muscle loss with aging, it’s a matter of quality, not quantity.

While that all sounds grim, you have the ability to preserve—and even increase—your muscle mass as you grow older.

Physical activity such as resistance exercise inarguably plays a vital role in preserving muscle mass as you age; however, nutrition will have just as strong—if not an even stronger—influence on your ability to preserve and build muscle.

Optimizing Your Nutrient Intake to Combat Muscle Loss

As you may be aware, when it comes to providing your muscle fibers with the optimized nutrition they need to maintain themselves and grow, protein is the macronutrient to prioritize. When you don’t provide your body with enough protein, your body will lose the ability to keep up muscle mass and bone density.

Determining your ideal protein intake can be challenging. Studies have shown that many factors affect the quantity of protein your body requires on a daily basis, such as:

  • Age
  • Gender
  • Physical activity habits
  • Muscle mass to fat ratio

Keep in mind, too, that your muscle mass to fat ratio differs from your body mass index (BMI). It’s entirely possible to be quite thin and still have high levels of fat compared to lean muscle, which increases the likelihood that you’ll develop age-related sarcopenia.

According to findings published in Current Opinion in Clinical Nutrition and Metabolic Care, eating between 25 grams and 30 grams of protein with each meal “maximally stimulates muscle protein synthesis in both young and older adults.” The authors noted, however, that when elderly subjects consumed protein and carbohydrates together or ate less than 20 grams of protein per meal, that blunted muscle protein synthesis.

Choosing the right protein sources will ensure each gram does the most work. When it comes to selecting protein sources, there’s one element you should pay the closest attention to: their amino acid content. If you’re aging and seeking to combat muscle wasting, you’ll benefit the most from increasing your intake of an amino acid called leucine.

Why Leucine Matters So Much

Leucine, an essential amino acid (EAA) called a branched-chain amino acid (BCAA) because of its chemical structure, is one of the most important dietary regulators of mTOR activity. If the proportion of leucine in an essential amino acid mixture is increased to an amount that exceeds its normal contribution to the composition of dietary protein, that EAA supplement can then effectively activate mTOR in aging muscle.

However, leucine alone is not enough. You may have noticed that I did not recommend taking a leucine supplement, but rather an amino acid supplement formulated to contain a higher concentration of leucine. That’s because all nine essential amino acids need to be present in the proper proportion to produce new muscle protein.

You can think of leucine as the quarterback of a football team—it may be the pivot point of how the team performs, but without the other players the team is not going to have much success.

How the Other 8 Essential Amino Acids Contribute

When you consume a large amount of the EAA leucine, you increase the rate at which leucine gets broken down since the body is designed to maintain steady levels of EAAs. And since the enzyme that breaks down leucine is also responsible for metabolizing the other two essential BCAAs, valine and isoleucine, they also get broken down at an increased rate. Consequently, the proportions of valine and isoleucine in an EAA formulation containing abundant leucine must also be increased.

Lysine is another EAA with distinct characteristics—it is not transported into muscle as readily as other EAAs are. For this reason, the optimal profile of EAAs to maximally stimulate anabolic-resistant muscle includes proportionately more lysine than is reflected in the composition of muscle protein.

So, even though it may seem logical to provide EAAs for a muscle-building supplement in a profile similar to the makeup of muscle, adjustments can be made to boost the signal and improve delivery of amino acids to overcome the anabolic resistance that results in muscle loss.

The remaining five EAAs—phenylalanine, threonine, methionine, tryptophan, and histidine—also need to be included in a mixture of EAAs to maximally stimulate muscle protein synthesis. In order to include disproportionately high amounts of BCAAs and lysine, however, the proportionate contribution of these additional EAAs must be reduced below what occurs in muscle protein.

Muscle loss with aging is one of the inescapable characteristics of growing older. While age-related muscle loss is a normal part of the aging process, we can temper its effect with the nutritional support of essential amino acids (EAAs). It's Never Too Early to Combat Age-Related Muscle Loss There's nothing wrong with embracing the mentality that 40 is the new 20, but don't fool yourself into believing age is nothing more than a number. Growing older does come with certain physiological changes. Yet there's no reason your golden years can't be every bit as vibrant as your youth. And the sooner you acknowledge how the passage of time influences certain biological processes, the better off you'll be. As you grow older, age-related muscle loss, which scientists refer to as sarcopenia or age-related sarcopenia, begins to erode your lean muscle mass. This process likely begins earlier than you think. Once you reach the age of 30, you begin to lose between 3% and 8% of your overall muscle mass each decade. The rate of decline increases once you turn 60. Understanding Anabolic Resistance Muscle loss with aging occurs because as the years wear on, we lose the ability to make new muscle protein from dietary protein. The impaired ability to build new muscle protein is called anabolic resistance. When your body enters an anabolic resistant state, it has trouble getting the motor started. The starter for the motor, in this case, is a factor inside the muscle cells called mTOR. mTOR starts the whole process of protein synthesis. The activation of mTOR begins a cascade of responses that ultimately result in the initiation of protein synthesis. Together these responses are called initiation factors. In aging muscle, the reactivity of mTOR and the other initiation factors are blunted, and this is a basis of anabolic resistance. The Vicious Cycle of Age-Related Sarcopenia This ongoing loss of skeletal muscle mass leaves older adults with less control over their bodies. Age-related changes to your muscle tissue and muscle strength don't just influence your ability to excel during a strength-training workout, they also make you more prone to falls and other types of injuries. Age-related sarcopenia can kick off a vicious cycle: your muscle strength decreases, which limits your ability to carry out physical activity, which causes further muscle loss. Ultimately, this can result in what health care professionals refer to as frailty, a condition that leaves you extra-susceptible to external stressors more hearty individuals would be able to navigate with few to no lasting consequences. Researchers have identified age-related sarcopenia as the primary factor behind the frailty we associate with aging, such as an increased propensity to fall, compounded by a higher likelihood of suffering an injury such as a broken hip due to a fall and the decreased ability to heal in the aftermath of such an injury. The more frail you become, the greater the impact of each stressor. As the adverse effects of minor illnesses and injuries accumulate, individuals find it more and more challenging to live independently. Increased frailty also heightens the risk of early death. [infographic] How Muscle Loss Creates a Downward Spiral As your muscle strength decreases, it becomes more difficult to be physically active. This results in more lost muscle mass and strength, which can culminate in what health care professionals refer to as frailty. Frailty makes you more susceptible to stressors like illness and injury. The more frail you are, the greater the damage done by each subsequent stressor. Ultimately, it becomes more and more difficult for frail individuals to live on their own. Becoming increasingly frail also raises your risk of early death. [/infographic] While that all sounds grim, you have the ability to preserve—and even increase—your muscle mass as you grow older. Physical activity such as resistance exercise inarguably plays a vital role in preserving muscle mass as you age; however, nutrition will have just as strong—if not an even stronger—influence on your ability to preserve and build muscle. Optimizing Your Nutrient Intake to Combat Muscle Loss As you may be aware, when it comes to providing your muscle fibers with the optimized nutrition they need to maintain themselves and grow, protein is the macronutrient to prioritize. When you don't provide your body with enough protein, your body will lose the ability to keep up muscle mass and bone density. Determining your ideal protein intake can be challenging. Studies have shown that many factors affect the quantity of protein your body requires on a daily basis, such as: Age Gender Physical activity habits Muscle mass to fat ratio Keep in mind, too, that your muscle mass to fat ratio differs from your body mass index (BMI). It's entirely possible to be quite thin and still have high levels of fat compared to lean muscle, which increases the likelihood that you'll develop age-related sarcopenia. According to findings published in Current Opinion in Clinical Nutrition and Metabolic Care, eating between 25 grams and 30 grams of protein with each meal "maximally stimulates muscle protein synthesis in both young and older adults." The authors noted, however, that when elderly subjects consumed protein and carbohydrates together or ate less than 20 grams of protein per meal, that blunted muscle protein synthesis. Choosing the right protein sources will ensure each gram does the most work. When it comes to selecting protein sources, there's one element you should pay the closest attention to: their amino acid content. If you're aging and seeking to combat muscle wasting, you'll benefit the most from increasing your intake of an amino acid called leucine. Why Leucine Matters So Much Leucine, an essential amino acid (EAA) called a branched-chain amino acid (BCAA) because of its chemical structure, is one of the most important dietary regulators of mTOR activity. If the proportion of leucine in an essential amino acid mixture is increased to an amount that exceeds its normal contribution to the composition of dietary protein, that EAA supplement can then effectively activate mTOR in aging muscle. However, leucine alone is not enough. You may have noticed that I did not recommend taking a leucine supplement, but rather an amino acid supplement formulated to contain a higher concentration of leucine. That's because all nine essential amino acids need to be present in the proper proportion to produce new muscle protein. You can think of leucine as the quarterback of a football team—it may be the pivot point of how the team performs, but without the other players the team is not going to have much success. How the Other 8 Essential Amino Acids Contribute When you consume a large amount of the EAA leucine, you increase the rate at which leucine gets broken down since the body is designed to maintain steady levels of EAAs. And since the enzyme that breaks down leucine is also responsible for metabolizing the other two essential BCAAs, valine and isoleucine, they also get broken down at an increased rate. Consequently, the proportions of valine and isoleucine in an EAA formulation containing abundant leucine must also be increased. Lysine is another EAA with distinct characteristics—it is not transported into muscle as readily as other EAAs are. For this reason, the optimal profile of EAAs to maximally stimulate anabolic-resistant muscle includes proportionately more lysine than is reflected in the composition of muscle protein. So, even though it may seem logical to provide EAAs for a muscle-building supplement in a profile similar to the makeup of muscle, adjustments can be made to boost the signal and improve delivery of amino acids to overcome the anabolic resistance that results in muscle loss. The remaining five EAAs—phenylalanine, threonine, methionine, tryptophan, and histidine—also need to be included in a mixture of EAAs to maximally stimulate muscle protein synthesis. In order to include disproportionately high amounts of BCAAs and lysine, however, the proportionate contribution of these additional EAAs must be reduced below what occurs in muscle protein. [infographic] Building an Optimal Essential Amino Acid Blend to Address Age-Related Muscle Loss First and foremost, you'll want high concentrations of leucine, an EAA and BCAA. Leucine activates mTOR in aging muscle, helping to stimulate maintenance and growth. You'll also need all the other EAAs—think of leucine like a quarterback. No matter how skillful that player is, he still needs the rest of his team to win. For the best results, you'll want to increase the proportions of the other two essential BCAAs, valine and isoleucine. You'll also want to up the lysine content. To make room for these adjustments, you'll need to scale back on the amount of phenylalanine, threonine, methionine, tryptophan and histidine you include. [/infographic] The Science Behind How Essential Amino Acids Prevent and Reverse Age-Related Muscle Loss A wealth of research has been conducted on the link between amino acids and age-related declines in protein metabolism, muscle function, muscle growth, and more. The scientists behind one study set out to examine how an amino acid mixture enriched with leucine affected muscle protein metabolism in both young and elderly subjects. They found that ingesting the enriched EAA mixture resolved anabolic resistance in elderly subjects. The mixture of EAAs was 3 times more effective at stimulating muscle protein synthesis in older individuals on a gram-per-gram basis than was whey protein isolate, which is a very high-quality protein by traditional means of assessment. Another study showed that a specifically formulated EAA supplement decreased loss of muscle mass and strength that occurs with bed rest and recovery from hip replacement. This is especially relevant when it comes to preventing muscle loss associated with aging, as older individuals are more likely to experience extended hospitalization and more likely to suffer adverse consequences from the inactivity imposed by hospital stays. Yet another study demonstrated that daily supplementation with EAAs improved muscle mass and function in healthy, active elderly women. The authors wanted to determine whether essential amino acid supplementation improves post-absorptive muscle protein fractional synthesis rate, lean body mass, muscle strength, and other physiological processes. The randomized, double-blinded, placebo-controlled trial found that ingesting the essential amino acid blend stimulated the muscle protein fractional synthesis rate as well as IGF-1 protein expression. Overall, the authors concluded that EAA supplementation improved lean body mass as well as muscle protein synthesis and that it could be a means of offsetting the "debilitating effects" of age-related sarcopenia. [infographic] 5 Science-Backed Ways EAAs Offset Age-Related Muscle Loss Researchers have shown that an amino acid blend enriched with leucine resolved anabolic resistance in elderly subjects. An essential amino acid blend proved 3 times more effective at stimulating muscle protein synthesis than whey protein isolate. An EAA supplement reduced losses of muscle mass and strength related to bed rest. Daily supplementation with EAAs can improve muscle mass and function. Studies show that EAAs can improve lean body mass and muscle protein synthesis, making them a possible means of treating age-related sarcopenia. [/infographic] Key Takeaways to Help You Remain Healthy and Vital as You Age Experts from across the globe agree that both the loss of muscle mass and the loss of muscle strength are highly prevalent and important risk factors for disability and potential mortality as individuals age. This makes identifying treatments for age-related muscle loss a key priority when it comes not only to improving average life expectancy for older people, but also reducing health care costs and enhancing overall quality of life. Ensuring an optimal protein intake will form a foundational part of any successful strategy for maintaining muscle mass (and bone density!) as you age. The kind of protein you eat will be just as impactful as the amount. Leucine, an EAA and BCAA found in certain protein sources, makes uniquely significant contributions to the muscle maintenance and growth processes within the human body. Consuming amino acid supplements designed to contain higher concentrations of leucine (as well as certain other helper amino acids) can dramatically influence your body's ability to retain and increase lean muscle mass as you age. The difference between the effectiveness of EAAs and intact protein cannot be made up just by consuming more of the intact protein, because the optimal profile of EAAs will never be achieved with intact protein. If you're interested in learning more about the advantages of essential amino acid supplements compared to dietary protein sources, this article is an excellent place to start. And if you'd like a quick takeaway in a nutshell, here it is: when it comes to amino acids for muscle loss with aging, it’s a matter of quality, not quantity.

The Science Behind How Essential Amino Acids Prevent and Reverse Age-Related Muscle Loss

A wealth of research has been conducted on the link between amino acids and age-related declines in protein metabolism, muscle function, muscle growth, and more.

The scientists behind one study set out to examine how an amino acid mixture enriched with leucine affected muscle protein metabolism in both young and elderly subjects. They found that ingesting the enriched EAA mixture resolved anabolic resistance in elderly subjects. The mixture of EAAs was 3 times more effective at stimulating muscle protein synthesis in older individuals on a gram-per-gram basis than was whey protein isolate, which is a very high-quality protein by traditional means of assessment.

Another study showed that a specifically formulated EAA supplement decreased loss of muscle mass and strength that occurs with bed rest and recovery from hip replacement. This is especially relevant when it comes to preventing muscle loss associated with aging, as older individuals are more likely to experience extended hospitalization and more likely to suffer adverse consequences from the inactivity imposed by hospital stays.

Yet another study demonstrated that daily supplementation with EAAs improved muscle mass and function in healthy, active elderly women. The authors wanted to determine whether essential amino acid supplementation improves post-absorptive muscle protein fractional synthesis rate, lean body mass, muscle strength, and other physiological processes. The randomized, double-blinded, placebo-controlled trial found that ingesting the essential amino acid blend stimulated the muscle protein fractional synthesis rate as well as IGF-1 protein expression. Overall, the authors concluded that EAA supplementation improved lean body mass as well as muscle protein synthesis and that it could be a means of offsetting the “debilitating effects” of age-related sarcopenia.

Muscle loss with aging is one of the inescapable characteristics of growing older. While age-related muscle loss is a normal part of the aging process, we can temper its effect with the nutritional support of essential amino acids (EAAs). It's Never Too Early to Combat Age-Related Muscle Loss There's nothing wrong with embracing the mentality that 40 is the new 20, but don't fool yourself into believing age is nothing more than a number. Growing older does come with certain physiological changes. Yet there's no reason your golden years can't be every bit as vibrant as your youth. And the sooner you acknowledge how the passage of time influences certain biological processes, the better off you'll be. As you grow older, age-related muscle loss, which scientists refer to as sarcopenia or age-related sarcopenia, begins to erode your lean muscle mass. This process likely begins earlier than you think. Once you reach the age of 30, you begin to lose between 3% and 8% of your overall muscle mass each decade. The rate of decline increases once you turn 60. Understanding Anabolic Resistance Muscle loss with aging occurs because as the years wear on, we lose the ability to make new muscle protein from dietary protein. The impaired ability to build new muscle protein is called anabolic resistance. When your body enters an anabolic resistant state, it has trouble getting the motor started. The starter for the motor, in this case, is a factor inside the muscle cells called mTOR. mTOR starts the whole process of protein synthesis. The activation of mTOR begins a cascade of responses that ultimately result in the initiation of protein synthesis. Together these responses are called initiation factors. In aging muscle, the reactivity of mTOR and the other initiation factors are blunted, and this is a basis of anabolic resistance. The Vicious Cycle of Age-Related Sarcopenia This ongoing loss of skeletal muscle mass leaves older adults with less control over their bodies. Age-related changes to your muscle tissue and muscle strength don't just influence your ability to excel during a strength-training workout, they also make you more prone to falls and other types of injuries. Age-related sarcopenia can kick off a vicious cycle: your muscle strength decreases, which limits your ability to carry out physical activity, which causes further muscle loss. Ultimately, this can result in what health care professionals refer to as frailty, a condition that leaves you extra-susceptible to external stressors more hearty individuals would be able to navigate with few to no lasting consequences. Researchers have identified age-related sarcopenia as the primary factor behind the frailty we associate with aging, such as an increased propensity to fall, compounded by a higher likelihood of suffering an injury such as a broken hip due to a fall and the decreased ability to heal in the aftermath of such an injury. The more frail you become, the greater the impact of each stressor. As the adverse effects of minor illnesses and injuries accumulate, individuals find it more and more challenging to live independently. Increased frailty also heightens the risk of early death. [infographic] How Muscle Loss Creates a Downward Spiral As your muscle strength decreases, it becomes more difficult to be physically active. This results in more lost muscle mass and strength, which can culminate in what health care professionals refer to as frailty. Frailty makes you more susceptible to stressors like illness and injury. The more frail you are, the greater the damage done by each subsequent stressor. Ultimately, it becomes more and more difficult for frail individuals to live on their own. Becoming increasingly frail also raises your risk of early death. [/infographic] While that all sounds grim, you have the ability to preserve—and even increase—your muscle mass as you grow older. Physical activity such as resistance exercise inarguably plays a vital role in preserving muscle mass as you age; however, nutrition will have just as strong—if not an even stronger—influence on your ability to preserve and build muscle. Optimizing Your Nutrient Intake to Combat Muscle Loss As you may be aware, when it comes to providing your muscle fibers with the optimized nutrition they need to maintain themselves and grow, protein is the macronutrient to prioritize. When you don't provide your body with enough protein, your body will lose the ability to keep up muscle mass and bone density. Determining your ideal protein intake can be challenging. Studies have shown that many factors affect the quantity of protein your body requires on a daily basis, such as: Age Gender Physical activity habits Muscle mass to fat ratio Keep in mind, too, that your muscle mass to fat ratio differs from your body mass index (BMI). It's entirely possible to be quite thin and still have high levels of fat compared to lean muscle, which increases the likelihood that you'll develop age-related sarcopenia. According to findings published in Current Opinion in Clinical Nutrition and Metabolic Care, eating between 25 grams and 30 grams of protein with each meal "maximally stimulates muscle protein synthesis in both young and older adults." The authors noted, however, that when elderly subjects consumed protein and carbohydrates together or ate less than 20 grams of protein per meal, that blunted muscle protein synthesis. Choosing the right protein sources will ensure each gram does the most work. When it comes to selecting protein sources, there's one element you should pay the closest attention to: their amino acid content. If you're aging and seeking to combat muscle wasting, you'll benefit the most from increasing your intake of an amino acid called leucine. Why Leucine Matters So Much Leucine, an essential amino acid (EAA) called a branched-chain amino acid (BCAA) because of its chemical structure, is one of the most important dietary regulators of mTOR activity. If the proportion of leucine in an essential amino acid mixture is increased to an amount that exceeds its normal contribution to the composition of dietary protein, that EAA supplement can then effectively activate mTOR in aging muscle. However, leucine alone is not enough. You may have noticed that I did not recommend taking a leucine supplement, but rather an amino acid supplement formulated to contain a higher concentration of leucine. That's because all nine essential amino acids need to be present in the proper proportion to produce new muscle protein. You can think of leucine as the quarterback of a football team—it may be the pivot point of how the team performs, but without the other players the team is not going to have much success. How the Other 8 Essential Amino Acids Contribute When you consume a large amount of the EAA leucine, you increase the rate at which leucine gets broken down since the body is designed to maintain steady levels of EAAs. And since the enzyme that breaks down leucine is also responsible for metabolizing the other two essential BCAAs, valine and isoleucine, they also get broken down at an increased rate. Consequently, the proportions of valine and isoleucine in an EAA formulation containing abundant leucine must also be increased. Lysine is another EAA with distinct characteristics—it is not transported into muscle as readily as other EAAs are. For this reason, the optimal profile of EAAs to maximally stimulate anabolic-resistant muscle includes proportionately more lysine than is reflected in the composition of muscle protein. So, even though it may seem logical to provide EAAs for a muscle-building supplement in a profile similar to the makeup of muscle, adjustments can be made to boost the signal and improve delivery of amino acids to overcome the anabolic resistance that results in muscle loss. The remaining five EAAs—phenylalanine, threonine, methionine, tryptophan, and histidine—also need to be included in a mixture of EAAs to maximally stimulate muscle protein synthesis. In order to include disproportionately high amounts of BCAAs and lysine, however, the proportionate contribution of these additional EAAs must be reduced below what occurs in muscle protein. [infographic] Building an Optimal Essential Amino Acid Blend to Address Age-Related Muscle Loss First and foremost, you'll want high concentrations of leucine, an EAA and BCAA. Leucine activates mTOR in aging muscle, helping to stimulate maintenance and growth. You'll also need all the other EAAs—think of leucine like a quarterback. No matter how skillful that player is, he still needs the rest of his team to win. For the best results, you'll want to increase the proportions of the other two essential BCAAs, valine and isoleucine. You'll also want to up the lysine content. To make room for these adjustments, you'll need to scale back on the amount of phenylalanine, threonine, methionine, tryptophan and histidine you include. [/infographic] The Science Behind How Essential Amino Acids Prevent and Reverse Age-Related Muscle Loss A wealth of research has been conducted on the link between amino acids and age-related declines in protein metabolism, muscle function, muscle growth, and more. The scientists behind one study set out to examine how an amino acid mixture enriched with leucine affected muscle protein metabolism in both young and elderly subjects. They found that ingesting the enriched EAA mixture resolved anabolic resistance in elderly subjects. The mixture of EAAs was 3 times more effective at stimulating muscle protein synthesis in older individuals on a gram-per-gram basis than was whey protein isolate, which is a very high-quality protein by traditional means of assessment. Another study showed that a specifically formulated EAA supplement decreased loss of muscle mass and strength that occurs with bed rest and recovery from hip replacement. This is especially relevant when it comes to preventing muscle loss associated with aging, as older individuals are more likely to experience extended hospitalization and more likely to suffer adverse consequences from the inactivity imposed by hospital stays. Yet another study demonstrated that daily supplementation with EAAs improved muscle mass and function in healthy, active elderly women. The authors wanted to determine whether essential amino acid supplementation improves post-absorptive muscle protein fractional synthesis rate, lean body mass, muscle strength, and other physiological processes. The randomized, double-blinded, placebo-controlled trial found that ingesting the essential amino acid blend stimulated the muscle protein fractional synthesis rate as well as IGF-1 protein expression. Overall, the authors concluded that EAA supplementation improved lean body mass as well as muscle protein synthesis and that it could be a means of offsetting the "debilitating effects" of age-related sarcopenia. [infographic] 5 Science-Backed Ways EAAs Offset Age-Related Muscle Loss Researchers have shown that an amino acid blend enriched with leucine resolved anabolic resistance in elderly subjects. An essential amino acid blend proved 3 times more effective at stimulating muscle protein synthesis than whey protein isolate. An EAA supplement reduced losses of muscle mass and strength related to bed rest. Daily supplementation with EAAs can improve muscle mass and function. Studies show that EAAs can improve lean body mass and muscle protein synthesis, making them a possible means of treating age-related sarcopenia. [/infographic] Key Takeaways to Help You Remain Healthy and Vital as You Age Experts from across the globe agree that both the loss of muscle mass and the loss of muscle strength are highly prevalent and important risk factors for disability and potential mortality as individuals age. This makes identifying treatments for age-related muscle loss a key priority when it comes not only to improving average life expectancy for older people, but also reducing health care costs and enhancing overall quality of life. Ensuring an optimal protein intake will form a foundational part of any successful strategy for maintaining muscle mass (and bone density!) as you age. The kind of protein you eat will be just as impactful as the amount. Leucine, an EAA and BCAA found in certain protein sources, makes uniquely significant contributions to the muscle maintenance and growth processes within the human body. Consuming amino acid supplements designed to contain higher concentrations of leucine (as well as certain other helper amino acids) can dramatically influence your body's ability to retain and increase lean muscle mass as you age. The difference between the effectiveness of EAAs and intact protein cannot be made up just by consuming more of the intact protein, because the optimal profile of EAAs will never be achieved with intact protein. If you're interested in learning more about the advantages of essential amino acid supplements compared to dietary protein sources, this article is an excellent place to start. And if you'd like a quick takeaway in a nutshell, here it is: when it comes to amino acids for muscle loss with aging, it’s a matter of quality, not quantity.

Key Takeaways to Help You Remain Healthy and Vital as You Age

Experts from across the globe agree that both the loss of muscle mass and the loss of muscle strength are highly prevalent and important risk factors for disability and potential mortality as individuals age. This makes identifying treatments for age-related muscle loss a key priority when it comes not only to improving average life expectancy for older people, but also reducing health care costs and enhancing overall quality of life.

Ensuring an optimal protein intake will form a foundational part of any successful strategy for maintaining muscle mass (and bone density!) as you age. The kind of protein you eat will be just as impactful as the amount. Leucine, an EAA and BCAA found in certain protein sources, makes uniquely significant contributions to the muscle maintenance and growth processes within the human body.

Consuming amino acid supplements designed to contain higher concentrations of leucine (as well as certain other helper amino acids) can dramatically influence your body’s ability to retain and increase lean muscle mass as you age.

The difference between the effectiveness of EAAs and intact protein cannot be made up just by consuming more of the intact protein, because the optimal profile of EAAs will never be achieved with intact protein. If you’re interested in learning more about the advantages of essential amino acid supplements compared to dietary protein sources, this article is an excellent place to start.

And if you’d like a quick takeaway in a nutshell, here it is: when it comes to amino acids for muscle loss with aging, it’s a matter of quality, not quantity.

The Relationship Between Energy and Amino Acids

Energy is one of the primary markers of health. When people are asked about their health, low energy is often a common complaint. What many people don’t realize, however, is that energy and amino acids go hand in hand.

Energy is one of the primary markers of health. When people are asked about their health, low energy is often a common complaint. Likewise, when people are asked to identify a benefit from a nutritional supplement, “improved energy” is often the first thing they report. What many people don’t realize, however, is that energy and amino acids go hand in hand.

Almost everyone, even the most energetic among us, desires more energy. So it’s no accident that energy drinks have become so popular. However, the concept of energy is somewhat vague. What does having energy really mean?

To understand the relationship between energy and amino acids, we must first distinguish between physical and mental energy. These two types of energy are clearly related, but distinct. By considering physical and mental energy separately, we can better understand the physiologic basis for each.

Energy and Amino Acids: What Fuels Our Bodies?

Physical energy requires not just fuel for our bodies but also all the necessary vitamins and cofactors—the inorganic substances needed for certain enzymes to carry out their functions—required to convert food to an energy form our cells can utilize.

Assuming all vitamins and cofactors are available, the energy necessary for physiologic functions is derived from combining carbohydrates, fats, proteins, and (in some cases) alcohol with oxygen in a process known as oxidation. These energy substrates—molecules acted on by an enzyme—can thus be considered the “fuel” of the body.

The major form of chemical energy in the body is a compound called adenosine triphosphate (ATP). Energy is released when ATP is broken down to adenosine diphosphate (ADP) and phosphate.

ATP is regenerated by the metabolism of the macronutrient (food required in large amounts for optimum nutrition) energy substrates mentioned above as well as by the oxidation of amino acids.

Chemical Energy and Mitochondria

The energy needed to perform physical functions such as exercise comes from the chemical energy stored in ATP. ATP is the universal fuel used by all cells.

In general, food is digested and absorbed as its basic components (glucose and other simple sugars, fatty acids, and amino acids), which are then used for structural needs, stored away, or oxidized for energy.

The oxidation of nutrients into chemical energy involves complex biochemical pathways. The Krebs cycle, named for its discoverer, Sir Hans Adolf Krebs—and also known as the citric acid or tricarboxylic acid (TCA) cycle—involves a series of chemical reactions in which carbon structures derived from carbohydrates, fats, and proteins are metabolized, with the production of ATP as a byproduct.

The TCA cycle operates inside mitochondria, which are specialized organelles within cells that are responsible for “digesting” nutrients and turning them into energy.

The energy and amino acid relationship.

Oxidation of Amino Acids for ATP Production

The majority of physical energy comes from the oxidation of fats and carbohydrates. However, every amino acid in the body can potentially be oxidized to produce ATP.

The amount of oxidation undergone by the essential amino acids (or EAAs)—the nine dietary amino acids that can’t be produced in the body and must be obtained from food—determines how much of each essential amino acid you need in a day.

The amount of protein synthesized by the body will decrease if a steady supply of EAAs is not maintained, leading to conditions such as muscle loss and impaired immune function. Therefore, any EAA that is oxidized must be replaced through the diet.

The oxidation of EAAs is important physiologically even though only a minimal amount of total energy production is derived from this process. For example, at rest, less than 10% of energy production comes from the oxidation of amino acids.

Exercise greatly increases the requirements for ATP, and part of that ATP comes from amino acid oxidation. This is one reason why the consumption of a number of whole foods and supplements, including whey protein, is recommended in the field of sports nutrition both pre-workout and post. However, amino acid oxidation does not increase uniformly during exercise.

Among the EAAs, there is a selective increase in the oxidation of leucine. However, even with the increase seen during exercise, leucine oxidation provides only about 3% to 4% of energy for ATP production. Yet leucine plays a crucial role in regulating protein synthesis and other metabolic processes, so extra leucine needs to be consumed after exercise to replace what was oxidized.

While amino acids, particularly EAAs, do not play a major role in overall energy production, there are a number of aspects of amino acid oxidation that are important for the body’s metabolic regulation. To understand the critical nature of EAA oxidation is to appreciate that the body regulates the availability of all EAAs at a relatively constant level.

Consuming a high-protein meal causes EAA availability to increase. This increased concentration of EAAs stimulates their oxidation and minimizes changes in EAA availability. By contrast, if you do not consume enough EAAs through your diet, metabolic adaptations occur that reduce the rate of EAA oxidation.

The oxidation of specific amino acids is important for the body. For example, the availability of certain amino acids depends on the oxidation of other amino acids.

Take tyrosine, for example. This amino acid is produced in the liver from the oxidation of the EAA phenylalanine. Maintaining an adequate amount of tyrosine in the blood is critical, as tyrosine is a precursor of the neurotransmitters dopamine, norepinephrine, and epinephrine.

Specific tissues and organs also have metabolic preferences for certain amino acids. Most prominently, glutamine (a nonessential amino acid) is a preferred substrate for the gut.

Amino Acids Augment Mitochondria

Only recently have we begun to appreciate the difference in energy levels the number of available mitochondria and their ability to operate at full capacity can make. Both amino acid supplementation and exercise are known to increase numbers of mitochondria and enhance their function.

By contrast, alcohol or drug use has been shown to induce mitochondrial defects by increasing oxidative stress and damaging mitochondrial genetic material—deoxynucleic acid, or DNA. When alcohol damages mitochondrial DNA, it impairs mitochondrial function, which further increases oxidative cell stress, leading to a vicious cycle of accumulating cell damage and decreased energy production over time.

Mental Energy: What Balances Our Brains?

Energy drinks typically contain caffeine (with a range of 6 to 242 mg of caffeine, according to Consumer Reports) and perhaps some B vitamins.

Whether used to help one wake up first thing in the morning or as an afternoon pick-me-up, these beverages clearly aid in sharpening concentration and increasing the body’s overall feeling of energy.

Surprisingly, when it comes to maintaining mental energy and focus, amino acids play as important a role as caffeine. In contrast to caffeine, however, amino acids impact mental energy by modulating neurotransmitters within the brain.

Many of the brain’s neurotransmitters are produced through the conversion of amino acids as they pass through the blood-brain barrier. In addition, two amino acids—glutamate and aspartate—are themselves considered neurotransmitters.

The interaction of neurotransmitters in the brain determines many aspects of behavior. To simplify a very complex system, the key determinant of mental energy is the balance between the neurotransmitters dopamine (excitatory) and serotonin (inhibitory).

The amounts of dopamine and serotonin in the brain are dependent on the availability of the precursors for their productionTyrosine is the amino acid precursor of dopamine, and tryptophan is the amino acid precursor of serotonin.

Tyrosine is also derived from the oxidation of phenylalanine. However, neither phenylalanine nor tryptophan is made in the body, as both are EAAs.

Increasing the amount of phenylalanine consumed in the diet will, via conversion to tyrosine, increase mental energy by increasing the amount of dopamine in the brain.

Conversely, increasing tryptophan consumption, such as through the use of the dietary supplement L-tryptophan, will induce a feeling of sleepiness or lack of energy by promoting serotonin production.

Amino Acid Balance and Mental and Physical Energy

Amino acids help support both physical and mental energy via a wide range of actions. While supplementation with individual amino acids may produce particular reactions, disrupting the body’s balance by consuming a single or small combination of amino acids may be counterproductive when it comes to other functions.

An amino acid supplement containing relatively high levels of phenylalanine (tyrosine is nearly insoluble and difficult to add to a dietary supplement) and low levels of tryptophan can provide mental sharpness and focus. However, an isolated increase in phenylalanine can also induce Parkinson-like symptoms in susceptible individuals.

Likewise, consumption of leucine can counter the accelerated rate of oxidation that occurs during exercise, but the use of leucine in isolation will activate the oxidation of valine and isoleucine, thereby limiting muscle protein synthesis.

Consequently, to replace the oxidized leucine and enhance post-workout muscle recovery, it is necessary to provide all three of the branched-chain amino acids, or BCAAs—leucine, isoleucine, and valine.

Finally, all EAAs must be available in sufficient quantities to stimulate muscle protein synthesis, which is the metabolic basis for increased muscle growth, strength, and function.

Hence, the gold standard approach for the maintenance of both mental and physical energy involves choosing a free-form amino acid formulation that takes into account not only the direct actions of the component amino acids but also the importance of maintaining a relative balance of EAAs to sustain maximal benefit.