According to the American Heart Association, cardiovascular diseases affect almost half of all adults in the United States. Moreover, more Americans die of heart disease each year than of any other cause. And the Centers for Disease Control and Prevention (CDC) estimates that approximately half of all adults in the United States have at least one of the three main risk factors for heart disease. These alarming statistics certainly call for serious action. But beyond the usual—and quite appropriate—recommendations for eating a healthy diet, getting regular exercise, and not smoking, a growing number of recent studies are suggesting that amino acids just might be the new indispensable addition to a heart-healthy lifestyle. In this article, we’re going to explore these latest findings and discuss how amino acids for the heart may be just what the doctor ordered.
Blood Pressure and Heart Disease
According to the CDC, the three key risk factors for cardiovascular disease are high cholesterol, smoking, and high blood pressure.
Elevated blood pressure, or hypertension, contributes to the development of heart disease by narrowing the blood vessels, which in turn decreases blood flow and causes the heart to have to work harder to pump blood out to the body.
Over time, this increased stress can raise the risk of a number of heart-related consequences, including cardiovascular events like angina (severe chest pain) and myocardial infarction (heart attack) as well as:
- Coronary artery disease
- Dilated cardiomyopathy
- Heart failure
- Kidney disease
- Vision loss
- Sexual dysfunction
However, studies have found that by lowering blood pressure a mere 5 millimeters of mercury diastolic—the bottom number in a blood pressure reading, corresponding to the relaxation phase of the heartbeat—an individual’s risk of having a stroke goes down by approximately 34% and their risk of ischemic heart disease by 21%.
Blood Pressure and Amino Acids for the Heart
Amino acids are known as the building blocks of life because they combine in a myriad of ways to form all the protein found in our bodies. And protein is not only the second most abundant substance in the body after water but is also involved in regulating almost every biochemical reaction required for survival.
Eleven of the 20 amino acids we require for life are called nonessential amino acids, as the body can (usually) manufacture them on its own. However, the other nine are called essential amino acids because we must get them from our daily protein intake.
Branched-Chain Amino Acids
As mentioned, more and more studies have found a link between amino acids and improved cardiac function. What’s more, levels of amino acids in the body may even act as important biomarkers of overall health.
For example, a 2016 study found that higher intakes of the branched-chain amino acids (BCAAs) isoleucine, leucine, and valine are associated with a lower incidence of high blood pressure, inflammation, and insulin resistance—another risk factor for cardiovascular disease.
This latter finding is especially interesting, as some researchers have hypothesized a link between BCAAs and insulin resistance and, in turn, the development of type 2 diabetes. However, this study is one of many that’s instead demonstrated that supplementing with BCAAs can actually improve insulin sensitivity.
In addition, multiple studies have found that disorders of amino acid metabolism that affect an individual’s ability to properly metabolize BCAAs may be offset by ingesting BCAAs with other nutrients.
Whey protein, for example, contains both BCAAs and a substance called lactokinin, which helps blood vessels relax by acting as a natural angiotensin-converting enzyme inhibitor.
Good food sources of BCAAs include:
Arginine and Citrulline
One of the standout amino acids for heart health is arginine, or L-arginine. This conditionally essential amino acid acts as a precursor of nitric oxide—a potent vasodilator that helps blood vessels relax and improves circulation throughout the body.
In fact, a 2010 study found that supplementing with L-arginine helps improve blood flow throughout the body by decreasing systolic blood pressure and increasing elasticity of blood vessel walls.
The amino acid citrulline also acts as a precursor of nitric oxide, as it converts to arginine in the kidneys. Interestingly, it also takes longer for the body to metabolize citrulline, which leads to even higher blood levels of arginine than those seen when taking arginine supplements. For this reason, citrulline may be even more effective for increasing levels of arginine in the blood.
Good dietary sources of arginine and citrulline include:
- Dark chocolate
- Pumpkin seeds
The amino acid carnitine helps transport fatty acids into the mitochondria—the energy centers of the cells (the production of which, incidentally, is stimulated by the BCAA leucine). Fatty acids are the main fuel used by the mitochondria for creating the primary form of energy used by the cells—adenosine triphosphate (ATP).
However, if the body doesn’t have enough carnitine, the production of ATP from fatty acids won’t occur at maximal capacity. And the heart muscle’s preferred form of energy comes from these long-chain fatty acids.
In addition, carnitine helps eliminate toxins from the mitochondria and provides a protective effect against oxidative stress by acting as a powerful antioxidant. And carnitine may also increase nitric oxide production.
A 2009 study found that participants who received carnitine (in the form of the dietary supplement acetyl-L-carnitine) experienced decreases in systolic blood pressure ranging from 5.4% to 6.2%—results that were thought to be related to increases in a protein known to have a positive effect on nitric oxide levels.
Another study from the same year demonstrated that a combination of alpha-lipoic acid and acetyl-L-carnitine was associated with a significant reduction in systolic blood pressure in participants with systolic blood pressures that were already higher than average as well as those with insulin resistance.
It’s important to note that most people usually don’t require supplemental carnitine, as it tends to be synthesized in sufficient quantities from the amino acids lysine and methionine.
However, in people who are truly deficient, it can be difficult to get enough additional lysine and methionine in the diet to have a significant impact on carnitine production. In cases such as these, carnitine supplementation is the most effective way to increase availability of this important amino acid.
Rich food sources of carnitine include:
- Dairy products
Glycine is a nonessential amino acid that’s probably best known for its role in building and maintaining collagen. In fact, it’s the most abundant amino acid in collagen, which itself is the most abundant type of protein in the body. Moreover, glycine is known to protect against oxidative stress by helping the body make glutathione—the so-called master antioxidant.
And studies have found that glycine’s involvement in the formation of both collagen and glutathione also makes it effective in the treatment of blood pressure.
For example, a 2006 study on rats found that glycine supplementation helped lower blood pressure via its role in collagen and glutathione production and by increasing circulating levels of nitric oxide. A 2013 human study revealed similar findings, demonstrating a significant decrease in systolic blood pressure in men who supplemented with glycine.
Good dietary sources of glycine include:
- Egg whites
- Sesame seeds
Taurine is the most abundant, semi-essential, sulfur-containing amino acid in the body. It’s known to promote cardiovascular health and guard against insulin resistance and has been shown to protect against heart failure in studies performed on animals.
In addition, studies have demonstrated a link between higher levels of taurine and decreased risk of death from heart disease as well as lower blood pressure and cholesterol levels.
A 2011 study found that taurine inhibits inflammation and oxidative stress and increases production of nitric oxide, leading to a positive effect on both blood pressure and arterial elasticity.
Another study from the same year, this time on rats, demonstrated that a combination of taurine supplementation and exercise can prevent hypertension and increase exercise capacity.
Finally, a 2016 study found that taurine supplementation in prehypertensive individuals—particularly those with high-normal blood pressure—effectively reduces blood pressure and improves vascular function.
Rich food sources of taurine include:
- Dark poultry meat
Amino Acids and Balance
Before you run out and look for an amino acid supplement to assist with heart health, it’s important to remember that amino acids provide the most benefits when used as part of a balanced formula that contains all nine essential amino acids—a fact that’s been borne out by a number of recent studies.
For instance, a 2015 study of nearly 2,000 women with healthy body mass indexes (BMIs), published in the Journal of Nutrition (J Nutr), found that women who ate the highest levels of seven specific amino acids had the greatest improvements in both blood pressure and blood vessel stiffness.
The findings of this study were so significant that they even led researchers to conclude that amino acid intake is as important for healthy blood pressure and blood vessels as getting sufficient exercise, reducing salt and alcohol consumption, and not smoking.
The seven amino acids found in this study to have a protective effect on heart health were:
Moreover, a 2010 clinical trial published in the International Dairy Journal (Int Dairy J) found that young adults with elevated systolic and diastolic blood pressure who drank a beverage containing 28 grams of either hydrolyzed or nonhydrolyzed whey protein every day for 6 weeks had significant decreases in both systolic and diastolic blood pressure and mean arterial pressure.
And a 2016 study published in the American Journal of Clinical Nutrition (Am J Clin Nutr) demonstrated that adults with prehypertension and mild hypertension who drank 56 grams a day of nonhydrolyzed milk protein (whey or calcium caseinate) for 8 weeks decreased their blood pressure and lipid levels and had improved vascular function.
As you can see, there’s an abundance of research pointing to the potential benefits of amino acids for the heart. And when included as part of a balanced formula of all nine essential amino acids, these important building blocks of life could prove to be an integral part of a heart-healthy lifestyle.