Hypothyroidism is a condition that occurs when your thyroid gland doesn't produce enough thyroid hormones. (1)
There are many glands in the body, but the thyroid gland is the small, butterfly-shaped organ at the base of your neck that makes hormones that regulate your metabolism — which affects how the body uses energy — and other processes. (2)
While your body goes through hormonal changes every day (hello, mood swings!), big dips — like those that occur during hypothyroidism — can signal danger, as a lack of thyroid hormone production causes the body’s functions to slow down.
Not to mention, an underactive or overactive thyroid (called hyperthyroidism) can affect your waistline. People with hypothyroidism experience a slower metabolic rate, which is generally associated with some amount — about 5 to 10 pounds — of weight gain, usually due to accumulation of salt and water in the body. (3)
The signs and symptoms of hypothyroidism often develop slowly over the years and could be mistaken for natural changes with aging. (4)
Women who are over age 60, as well as men who are aging, should look out for these potential symptoms of hypothyroidism:
Hypothyroidism is most common in middle-aged and older women. But sometimes infants and children can develop the condition, such as infants who were born without a thyroid gland or who have a thyroid gland that doesn’t function properly. (4) Congenital hypothyroidism occurs in about 1 in 2,000 to 1 in 4,000 newborns. (5) If undiagnosed, it can lead to increasingly severe symptoms, and even physical and mental disabilities. (4)
Symptoms of hypothyroidism in infants may include:
Symptoms of hypothyroidism in children and teens are similar to symptoms in adults and can include: (4,6)
If you have many of the common symptoms of hypothyroidism, such as dry skin, constipation, fatigue, and a hoarse voice, you could make an appointment with your doctor to check for hypothyroidism. (4) Your doctor can perform various screenings, including: (7)
If these tests show an elevated thyroid-stimulating hormone (TSH) and low levels of thyroid hormones, like free T4, total T3, or free T3, it may be an indication that you have hypothyroidism, says Mayumi Endo, MD, an endocrinologist at The Ohio State University Wexner Medical Center in Columbus.
Anyone can develop hypothyroidism, but you're at higher risk for it if you're a woman older than 60.
Other risk factors for hypothyroidism include:
It's the most common cause of underactive thyroid in the United States.
Hashimoto's thyroiditis typically affects middle-aged women, but it can happen in anyone. It affects about 5 in 100 people, and is 8 times more common in women than men. (9) About 10 to 12 percent of the population has the antibodies that cause Hashimoto’s thyroiditis, but not all of these individuals will develop thyroid dysfunction. (10) Currently, the causes of Hashimoto’s thyroiditis are unknown, but experts think they may be due to a combination of genes and an external trigger, like a virus. (9)
Doctors can detect the condition by testing your thyroid function. Treatment usually involves thyroid hormone replacement medication.
Your thyroid gland must have correct amounts of the mineral iodine in order to make thyroid hormones.
Consuming too little iodine can lead to hypothyroidism. Too much iodine may also cause or worsen hypothyroidism.
Iodine is found in foods such as seaweed, seafood, and iodized salt.
In some areas of the world, iodine deficiency is common, but it's rare in the United States because most forms of table salt are fortified with the mineral. So iodine levels are not routinely tested in the evaluation for hypothyroidism.
A thyroidectomy — surgery to remove all or part of your thyroid gland — can slow or stop the production of thyroid hormones and cause hypothyroidism. The operation is fairly common: In 2011, for example, more than 70,000 patients in the United States received a thyroidectomy (the most common cause for surgery was cancer). (11)
People with thyroid cancer, goiter (an enlarged thyroid), thyroid nodules, or Graves' disease may need to undergo this procedure.
Underactive thyroid may also be caused by:
Medication Many different types of medication can affect the thyroid gland. Lithium is a common drug that can cause hypothyroidism.
Also, medicines such as radioactive iodine — which is used to treat hyperthyroidism (overactive thyroid) — may impair your thyroid function.
In addition, there are many other drugs that can affect your thyroid gland, such as amiodarone, any chemotherapy category with tyrosine kinase inhibitor and check-point inhibitors, steroids, interferon alpha, and more, Dr. Endo says. Check with your doctor if you are concerned about any medication you are taking.
Radiation Therapy Radiation for cancers of the head and neck can lead to hypothyroidism.
Congenital Problems Sometimes babies are born without a thyroid gland or with a deformed gland, which results in reduced thyroid function.
Rare Disorders Diseases that deposit abnormal substances in the thyroid can affect its ability to function. These diseases may include amyloidosis (a rare disease where amyloid proteins build up in organs like the heart and kidneys), sarcoidosis (a disease that involves the growth of inflammatory cells in the body), or hemochromatosis (the buildup of too much iron in the body).
Pregnancy About 15 percent of pregnant women may experience an increase in the size of their thyroid during pregnancy (returning to normal after). This can be a normal process to increase thyroid hormone production needed to support the pregnancy. (12)
The same antibodies that cause Hashimoto’s thyroiditis can be present in women who become pregnant. In the year following the pregnancy, women with these antibodies can have thyroid dysfunction (either hyperthyroidism or hypothyroidism).
A Pituitary Disorder When the pituitary gland fails to produce enough thyroid-stimulating hormone (TSH), hypothyroidism can occur. Usually this is caused by a tumor in the pituitary. (13) Such tumors typically occur in older adults, and about 10,000 pituitary tumors are diagnosed each year in the United States. (14)
Myxedema is advanced hypothyroidism, and occurs in patients who have had untreated and severe hypothyroidism for a long time. (15)
The condition is rare — one estimate notes the number of historical cases in medical literature hovers only around 300 total (16) — but it can be life-threatening. Researchers estimate that the mortality rate for myxedema is between 20 and 50 percent. (16)
Symptoms of myxedema include:
Endo says some of the major risks of living with hypothyroidism include hypothermia, cognitive impairment, coronary artery disease, and hyperlipidemia (a high concentration of fat, or lipids, in the blood). In addition, she says, patients with hyperlipidemia and coronary artery disease should be especially aware of their hypothyroidism risk.
Other potential long-term complications include decreased lung function, an abnormal enlargement of the thyroid gland, and even coma, when the body’s level of thyroid hormone become extremely low.
There are a number of treatments for hypothyroidism, usually involving medication. Some people also use alternative medicines to help them manage their disease.
Levothyroxine is a man-made thyroid hormone that works by replacing thyroxine, the hormone your body can no longer make in adequate amounts. It's typically taken daily to reverse symptoms of hypothyroidism. (17)
“Studies after studies show levothyroxine is the best treatment of choice,” Endo explains. She notes that some people are allergic to the generic form of levothyroxine, mostly due to the color dye. In that case, you can use either the levothyroxine 50 microgram (mcg) pills (these don’t have dye in them) or the brand Tirosint, although this is more expensive.
Levothyroxine may lower your cholesterol levels and help you return to a normal weight. The medicine causes very few side effects and is relatively inexpensive, with an average retail price of $16.73. (17) The generic form of the drug is covered by most Medicare and insurance plans. (18)
Treatment with levothyroxine is usually continued for the rest of your life, but your doctor may adjust your dose over time.
Some people with hypothyroidism choose to supplement their treatment with alternative medicines, often to help with symptoms like fatigue, weight gain, stress, and mental fog. (18) Treatments can include yoga, meditation, hypnosis, vitamins, or special diets. (19)
One small study of 20 female patients with hypothyroidism found that yoga helped patients manage their symptoms. (19)
While people with thyroid disease are often careful to eat a diet low in iodine (which can worsen hypothyroidism once a patient has it), or to take Vitamin D or calcium supplementation, no diet or nutrient can cure thyroid disease. (20, 19)
And many experts stress that while these complementary and alternative therapies can supplement traditional treatment, they cannot replace it. (21)
One treatment that medical doctors do not recommend? Natural dessicated thyroid products (either porcine or bovine products). The most common is the pig thyroid extract called Armour. Because the components of the pig’s thyroid hormone are very different from that of a human being, medical professionals recommend against using this agent, Endo says. These are most often prescribed by naturopathic doctors.
There's no medical evidence that any particular diet will improve the functioning of your thyroid gland, despite anecdotal claims seen online and elsewhere. (22)
If you're taking thyroid hormone replacement for hypothyroidism, you may want to avoid consuming certain foods within a few hours of taking your thyroid medication. Some foods, like calcium, iron, and multivitamins, may block absorption of the thyroid hormone, and so should be taken four hours apart from levothyroxine, Endo says.
Foods to limit with hypothyroidism:
Overall, it is most important for people with hypothyroidism to eat a well-balanced diet, rather than try to consume any particular food group, Endo says.
In patients older than 60, hypothyroidism becomes very common and increases with age. In fact, up to 1 in 4 patients in nursing homes may have undiagnosed hypothyroidism, according to the American Thyroid Association. (23)
Symptoms may include: (24)
Since symptoms may mimic normal aging, it’s important for a doctor to make an assessment and decide on a possible course of treatment, such as thyroid hormone replacement. (24) Doses of hormone treatment must be increased slowly, to prevent too much stress on other body systems, like the heart and central nervous system. (24)
Surprisingly, some studies have found that slightly elevated TSH levels could contribute to an extended lifespan. (24) These individuals had a slightly higher TSH with a normal T4 level, called subclinical hypothyroidism. People over age 65 with hypothyroidism should be treated, but they should also discuss the TSH treatment goal (a higher normal TSH goal may be better). Still, hypothyroidism in older adults should be treated, primarily to relieve symptoms and prevent myxedema. (25)