According to the American Thyroid Association, more than 12% of people in the United States will develop some type of thyroid disorder in the course of their lives. And the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) estimates that approximately 5% of Americans over the age of 12 have symptoms of hypothyroidism, or underactive thyroid. If left untreated, hypothyroidism can result in a number of serious health problems. So come with us as we delve into this common condition, uncover its causes and symptoms, and discuss available treatments and what you can do to take care of your thyroid and protect your long-term health.
What Is the Thyroid, and What Does It Do?
The thyroid is a small, butterfly-shaped gland that sits near the bottom of the neck, below the larynx, or voice box. The thyroid gland makes two main hormones, thyroxine (T4) and triiodothyronine (T3), the levels of which are controlled by another hormone called thyroid-stimulating hormone (TSH). TSH is in turn produced by the pituitary gland—an organ found in the brain that’s sometimes referred to as the body’s master gland.
Together, the thyroid hormones regulate the body’s use of energy and affect the function of almost every organ. In fact, many of the processes we take for granted, such as heartbeat, breathing, body temperature, metabolism, and menstrual cycles, couldn’t take place without thyroid hormones.
But sometimes the thyroid’s ability to produce enough hormones to maintain healthy functioning is compromised. And when this happens, hypothyroidism results.
Causes of Hypothyroidism
Hypothyroidism may be caused by a number of factors, from autoimmune diseases to iodine deficiency, but some of the most common causes include:
- Hashimoto’s thyroiditis
- Radiation therapy
Hashimoto’s thyroiditis, or Hashimoto’s disease, is the most common cause of hypothyroidism in America. An autoimmune disorder in which the immune system mistakes the thyroid for a foreign invader and creates antibodies against it, Hashimoto’s thyroiditis results in chronic inflammation of the thyroid that damages the gland’s ability to produce thyroid hormones.
People who’ve undergone thyroidectomy to treat certain thyroid diseases, including overactive thyroid (hyperthyroidism), thyroid nodules, and thyroid cancer, can develop hypothyroidism. Some forms of thyroid surgery preserve thyroid function by removing only part of the gland, but individuals who’ve had surgical removal of the entire gland must receive supplemental thyroid hormones for the rest of their lives.
People with head and neck cancers who undergo radiation—including radioactive iodine for the treatment of thyroid cancer or hyperthyroidism—may experience thyroid damage that leads to hypothyroidism.
In addition to the above, other less common causes of hypothyroidism may include:
- Congenital hypothyroidism: This type of hypothyroidism occurs when an infant is born with a thyroid gland that’s either defective or missing.
- Pituitary gland tumor: If the pituitary gland fails to produce adequate levels of TSH—usually as a result of a tumor—hypothyroidism can occur.
- Iodine deficiency: The trace mineral iodine is necessary for proper thyroid hormone production, and deficiencies can lead to hypothyroidism.
Risk Factors for Hypothyroidism
Although anyone can develop hypothyroidism, certain factors may predispose an individual to developing the condition. Some of the most common risk factors include:
- Family history: People with a family history of thyroid disorders are more likely to develop hypothyroidism.
- Sex: Women have a greater risk of developing hypothyroidism.
- Age: People over the age of 60 are at greater risk of having the condition.
- Autoimmune conditions: People with a history of other autoimmune disorders, such as type 1 diabetes and rheumatoid arthritis, have a higher risk of developing hypothyroidism.
Complications of Hypothyroidism
Many people may think of hypothyroidism as a relatively benign condition that causes little more than fatigue and weight gain. However, untreated hypothyroidism can lead to a number of serious health issues, including:
- Heart disease
- Heart failure
- Peripheral neuropathy
- Myxedema coma
Symptoms of Hypothyroidism
The symptoms seen in cases of hypothyroidism vary depending on the severity of the disease. And because the condition tends to develop slowly over many years, it can be easy to dismiss symptoms as merely the result of the aging process. However, as the disease continues to progress, symptoms will become harder to ignore. Some of the most common symptoms to watch out for include:
|Chronic fatigue||Cold intolerance|
|Constipation||Dry or puffy skin|
|Hair loss||Weight gain|
|Hoarseness||Muscle and joint pain|
|Muscle weakness||Joint swelling|
|Elevated cholesterol||Irregular menstrual periods|
|Decreased heart rate||Depression|
|Memory difficulties||Thyroid enlargement (goiter)|
To diagnose hypothyroidism, your health care provider will first speak with you regarding your symptoms and then perform a physical exam to evaluate for signs of the condition, including thyroid enlargement, dry skin, and slow heart rate. If findings lead your health care provider to suspect hypothyroidism, blood tests will then be conducted to assess thyroid hormone levels.
While the most commonly measured thyroid hormone is TSH, your doctor may choose to evaluate levels of T4 as well. A finding of elevated TSH levels and decreased T4 levels is indicative of clinical hypothyroidism. However, in cases where TSH is elevated but T4 is normal, a diagnosis of subclinical hypothyroidism may be given. If this occurs, your health care provider might choose to do nothing, or they might offer a trial of thyroid hormone replacement or recommend dietary changes and nutritional support.
After receiving a diagnosis of hypothyroidism, treatment usually involves thyroid hormone replacement in the form of levothyroxine—a synthetic hormone. This medication is provided in pill form and is usually given once a day. When therapy first begins, TSH will need to be checked on a regular basis to ensure the proper dosage has been prescribed.
If you experience symptoms of too much thyroid hormone, including increased appetite, insomnia, and palpitations, your dose of levothyroxine will need to be lowered. However, side effects are generally minimal after the appropriate dose is found, and treatment usually requires only yearly monitoring to make sure further dosage changes aren’t needed.
Diet and Nutrition
As mentioned, diet and nutrition play an important role in thyroid health and can be very helpful when used as adjunctive therapy in the treatment of hypothyroidism.
While people with hypothyroidism may be advised to limit their consumption of goitrogenic foods like broccoli and kale—as they may interfere with the production of thyroid hormones—there are many foods and nutritional supplements that can actually help support the thyroid and even decrease the need for medication. These include foods high in B vitamins, omega-3 fatty acids, and antioxidants as well as:
- Vitamin D: Studies have shown that people with hypothyroidism tend to have lower levels of vitamin D.
- Selenium: The thyroid gland contains more selenium than any other organ in the body and we must have this important mineral in order to convert inactive T4 into active T3 (triiodothyronine).
- Inositol: When used with selenium, inositol has been shown to decrease both TSH and the levels of antibodies seen in autoimmune thyroid disorders.
- Zinc: Like selenium, zinc is also required by the thyroid gland for converting T4 into T3.
- Ashwagandha: This well-known adaptogen not only helps the body adapt to stress but has also been shown in studies to assist in balancing thyroid hormone levels.
- Amino acids: Known as the building blocks of life, amino acids play a critical role in almost every biological process, including thyroid function. One amino acid in particular—tyrosine—is combined with iodine in the thyroid to create both T3 and T4.
If you’re experiencing symptoms of hypothyroidism, be sure to speak with your health care provider. Testing is quick and easy, and early treatment can help prevent long-term complications.