What is hypothyroidism?
Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland doesn’t produce enough of certain crucial hormones.
Hypothyroidism may not cause noticeable symptoms in the early stages. Over time, untreated hypothyroidism can cause a number of health problems, such as obesity, joint pain, infertility and heart disease.
Accurate thyroid function tests are available to diagnose hypothyroidism. Treatment with synthetic thyroid hormone is usually simple, safe and effective once you and your doctor find the right dose for you.
The thyroid gland is located in the front lower part of your neck. Hormones released by the gland travel through your bloodstream and affect nearly every part of your body, from your heart and brain, to your muscles and skin.
The thyroid controls how your body’s cells use energy from food, a process called metabolism. Among other things, your metabolism affects your body’s temperature, your heartbeat, and how well you burn calories. If you don’t have enough thyroid hormone, your body processes slow down. That means your body makes less energy, and your metabolism becomes sluggish.
The signs and symptoms of hypothyroidism vary, depending on the severity of the hormone deficiency. Problems tend to develop slowly, often over a number of years.
At first, you may barely notice the symptoms of hypothyroidism, such as fatigue and weight gain. Or you may simply attribute them to getting older. But as your metabolism continues to slow, you may develop more-obvious problems.
Hypothyroidism signs and symptoms may include:
- Increased sensitivity to cold
- Dry skin
- Weight gain
- Puffy face
- Muscle weakness
- Elevated blood cholesterol level
- Muscle aches, tenderness and stiffness
- Pain, stiffness or swelling in your joints
- Heavier than normal or irregular menstrual periods
- Thinning hair
- Slowed heart rate
- Impaired memory
- Enlarged thyroid gland (goiter)
Hypothyroidism in infants
Although hypothyroidism most often affects middle-aged and older women, anyone can develop the condition, including infants. Initially, babies born without a thyroid gland or with a gland that doesn’t work properly may have few signs and symptoms. When newborns do have problems with hypothyroidism, the problems may include:
- Yellowing of the skin and whites of the eyes (jaundice). In most cases, this occurs when a baby’s liver can’t metabolize a substance called bilirubin, which normally forms when the body recycles old or damaged red blood cells.
- A large, protruding tongue.
- Difficulty breathing.
- Hoarse crying.
- An umbilical hernia.
As the disease progresses, infants are likely to have trouble feeding and may fail to grow and develop normally. They may also have:
- Poor muscle tone
- Excessive sleepiness
When hypothyroidism in infants isn’t treated, even mild cases can lead to severe physical and mental retardation.
Hypothyroidism in children and teens
In general, children and teens who develop hypothyroidism have the same signs and symptoms as adults do, but they may also experience:
- Poor growth, resulting in short stature
- Delayed development of permanent teeth
- Delayed puberty
- Poor mental development
Causes of Hypothyroidism
The most common cause of hypothyroidism is Hashimoto’s thyroiditis. “Thyroiditis” is an inflammation of the thyroid gland. Hashimoto’s thyroiditis is an autoimmune disorder. With Hashimoto’s, your body produces antibodies that attack and destroy the thyroid gland. Thyroiditis may also be caused by a viral infection.
Other causes of hypothyroidism include:
- Radiation therapy to the neck area. Treating certain cancers, such as lymphoma, requires radiation to the neck. Radiation damages the cells in the thyroid. This makes it more difficult for the gland to produce hormone.
- Radioactive iodine treatment. This treatment is commonly prescribed to people who have an overactive thyroid gland, a condition known as hyperthyroidism. However, radiation destroys the cells in the thyroid gland. This usually leads to hypothyroidism.
- Use of certain medications . Certain medicines to treat heart problems, psychiatric conditions, and cancer can sometimes affect the production of thyroid hormone. These include amiodarone (Cordarone, Pacerone), , interferon alpha, and interleukin-2.
- Thyroid surgery . Surgery to remove the thyroid will lead to hypothyroidism. If only part of the thyroid is removed, the remaining gland may still be able to produce enough hormone for the body’s needs.
- Too little iodine in the diet. The thyroid needs iodine to produce thyroid hormone. Your body doesn’t make iodine, so you need to get it through your diet. Iodized table salt is rich in iodine. Other food sources of iodine include shellfish, saltwater fish, eggs, dairy products, and seaweed. Iodine deficiency is rare in the U.S.
- Pregnancy . The reason isn’t clear, but sometimes, inflammation of the thyroid occurs after pregnancy. This is called postpartum thyroiditis. Women with this condition usually have a severe increase in thyroid hormone levels followed by a sharp drop in thyroid hormone production. Most women with postpartum thyroiditis will regain their normal thyroid function.
- Problems with the thyroid at birth. Some babies may be born with a thyroid gland that did not develop correctly or does not work properly. This type of hypothyroidism is called congenital hypothyroidism. Most hospitals in the U.S. screen babies at birth for this disease.
- Pituitary gland damage or disorder. Rarely, a problem with the pituitary gland can interfere with the production of thyroid hormone. The pituitary gland makes a hormone, called thyroid-stimulating hormone (TSH), which tells your thyroid how much hormone it should make and release.
- Disorder of the hypothalamus. An extremely rare form of hypothyroidism can occur if the hypothalamus in the brain does not produce enough of a hormone called TRH. TRH affects the release of TSH from the pituitary gland.
Primary hypothyroidism is caused by a problem with the thyroid gland itself.
Secondary hypothyroidism occurs when another problem interferes with the thyroid’s ability to produce hormones. For example, the pituitary gland or hypothalamus produce hormones that trigger the release of thyroid hormone. A problem with one of these glands can make your thyroid underactive. Sometimes, an underactive thyroid that results from a problem with the hypothalamus is called tertiary hypothyroidism.
Hypothyroidism Risk Factors
Women, particularly older women, are more likely to develop hypothyroidism than men. You are also more likely to develop hypothyroidism if you have a close family member with an autoimmune disease. Other risk factors include:
- Race (being white or Asian)
- Age (growing older)
- Prematurely graying hair
- Autoimmune disorders such as type 1 diabetes, multiple sclerosis, rheumatoid arthritis, celiac disease, Addison’s disease, pernicious anemia, or vitiligo
- Bipolar disorder
- Down syndrome
- Turner syndrome
Diagnosis of Hypothyroidism
If you have symptoms of hypothyroidism, your doctor will order blood tests to check hormone levels. These may include:
- Thyroid-stimulating hormone (TSH)
- T4 (thyroxine)
Lower-than-normal T4 levels usually mean you have hypothyroidism. However, some people may have increased TSH levels while having normal T4 levels. This is called subclinical (mild) hypothyroidism. It is believed to be an early stage of hypothyroidism.
If your test results or physical exam of the thyroid are abnormal, your doctor may order a thyroid ultrasound, or thyroid scan, to check for nodules or inflammation.
If you have hypothyroidism, your doctor will prescribe a synthetic (man-made) thyroid hormone T4. You take this pill every day. Certain other medications can interfere with how your body absorbs synthetic thyroid hormone. Make sure you doctor knows about all the medicines, herbs, and supplements you take, including over-the-counter products.
You will need regular blood tests to check your thyroid hormone levels. Your doctor may need to adjust your medication dose from time to time.
Complications of Hypothyroidism
Untreated, hypothyroidism may cause:
- Heart problems
- Joint pain
Thyroid problems in a pregnant woman can affect the developing baby. During the first three months of pregnancy, the baby receives all thyroid hormone from its mother. If the mother has hypothyroidism, the baby does not get enough thyroid hormone. This can lead to problems with mental development.
Extremely low levels of thyroid hormone can cause a life-threatening condition called myxedema. Myxedema is the most severe form of hypothyroidism. A person with myxedema can lose consciousness or go into a coma. The condition can also cause the body temperature to drop very low, which can cause death.
How to take Vitamins to prevent hypothyroidism ?
For some people, managing hypothyroidism isn’t just about taking medications. They also turn to vitamins and other nutrients for help in managing the condition, which occurs when the thyroid doesn’t make enough thyroid hormone to keep the body running normally.
“Vitamins and nutrients can help fight the underlying causes of thyroid disorders, such as autoimmune processes and inflammation, and help improve a dysfunctional thyroid,” says Raphael Kellman, MD, a functional medicine physician in New York City and author of The Microbiome Diet.
However, it’s important to understand that no one should supplement with vitamins and minerals without talking to their doctor first. “You want to first know your individual levels of these vitamins and minerals, which you can find out with a blood test,” Dr. Kellman says. Results may reveal you have a nutrient deficiency that requires you to get a higher amount of a certain vitamin or supplement.
“You also want to make sure you have all the facts on the vitamins and minerals you’d like to supplement with,” says MaryAnne Metzak, RD, CDN, a registered dietitian based in New York. And it’s important to keep the lines of communication open between you and your doctor. “Your doctor needs to know exactly how much of each vitamin and supplement you’re taking in case you have a negative reaction,” Metzak says.
Here are specific nutrients that may be beneficial for hypothyroidism.
Iodine Is Needed to Make Thyroid Hormone
You need an adequate supply of iodine to make thyroid hormone. The recommended minimum iodine intake for most adults is 150 micrograms a day, according to the National Institutes of Health Office of Dietary Supplements. Good food sources include milk, cheese, poultry, eggs, kelp, and other seaweeds, Kellman says. “But you have to be careful with supplementing iodine because too much can be problematic and actually cause hypothyroidism,” he says.
It’s important to speak with your physicians before consuming any iodine supplements due to the adverse effects it can have on hypothyroidism. A review published in September 2014 study in the journal Endocrinology and Metabolism found that excessive levels of iodine are unsafe and could result in hypothyroidism and autoimmune thyroiditis such as Hashimoto’s thyroiditis.
Vitamin B Is Important for Thyroid Function
“Vitamin B is important for people with hypothyroidism because the B vitamins have many interactions with thyroid function and hormone regulation,” Metzak says. It’s best to take a nutritional supplement that includes the entire vitamin B complex, and you may need additional vitamin B12 if a blood test reveals your levels are low, she says. Good food sources of vitamin B include whole grains, legumes, nuts, milk, yogurt, meat, fish, eggs, seeds, and dark leafy greens.
Selenium Is Essential for Thyroid Hormone Metabolism
“Selenium supports efficient thyroid synthesis and metabolism,” says Denise Londergan, RD, MPH, a registered dietitian in Ohio. Selenium may also reduce levels of antibodies against thyroid peroxidase — an enzyme that plays an important role in the production of thyroid hormones — in people with hypothyroidism, according to a study published in 2018 in the journal Diagnostics. Foods that provide selenium include tuna, shrimp, salmon, sardines, scallops, lamb, chicken, beef, turkey, eggs, and shitake mushrooms. “Or you can take 100 to 200 micrograms of selenium in supplement form per day,” Kellman says.
Zinc Helps Synthesize Thyroid Hormone
In addition to selenium, zinc plays a role in the conversion of the thyroid hormone T4 to T3. Selenium and zinc are beneficial in improving thyroid function and hormone levels. According to a study in Hormones: The Journal of Endocrinology and Metabolism, zinc improves T3 levels significantly. Food sources of zinc include shellfish, mollusks, meat, legumes, and nuts. The recommended daily intake of zinc is 8 to 11 milligrams for adult women and men, respectively, according to the Office of Dietary Supplements.
Tyrosine, in Combination With Iodine, Produces Thyroid Hormone
“Tyrosine is a nutrient involved in thyroid hormone production and conversion,” Kellman says. One of the best ways to get more tyrosine, an amino acid, is to make sure you’re getting enough protein, Londergan says. Aim for 10 to 35 percent of your calories from protein each day.
Vitamin D Improves TSH Levels
“Research has shown a strong association with vitamin D deficiency and people with hypothyroidism,” Metzak says. In a study published in the November 2013 issue of the International Journal of Health Sciences, researchers looked at the vitamin D levels of 30 people with hypothyroidism and 30 who didn’t have the condition and found that the vitamin D levels were significantly lower in those with hypothyroidism. A study published in 2018 in the Indian Journal of Endocrinology and Metabolism found that vitamin D supplements improved TSH levels in subjects with hypothyroidism as well as thyroid antibodies in people with autoimmune thyroiditis. You can get vitamin D from fortified milk, yogurt, and orange juice. “Food sources of vitamin D are often not adequate, however,” Kellman says. He recommends supplements for those who are vitamin D deficient. Your doctor can let you know if that’s necessary, and which dosage is best for you.
As with any chronic condition, a healthy diet can go a long way with hypothyroidism. “Eat an anti-inflammatory diet full of lots of fruits and vegetables and unprocessed foods, and limit sugar,” Londergan says.
Some Supplements Can Affect Thyroid Medication
While there are plenty of vitamins and supplements that can help people with hypothyroidism, there are also some that may interfere with thyroid hormone absorption. According to the Mayo Clinic, supplements such as calcium, iron, multivitamins containing iron, and antacids containing magnesium or aluminum can potentially have interactions with thyroid medications. They should be taken several hours before or after your thyroid medication to avoid an interaction. Talk to your doctor before taking any of these supplements.