Thyroid disease is one of the most common conditions in America, yet the cause remains mysterious. More than 20 million people suffer from a thyroid disorder; some of them don’t even know it. They just feel awful. More than 80 million prescriptions are filled every year for thyroid hormones like levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid) and Armour desiccated thyroid. If we didn’t know better, we would say there is an epidemic of hypothyroidism in America.
Nobody knows exactly what makes the thyroid gland stop working properly. In many cases of hypothyroidism (an underactive thyroid), the immune system attacks the thyroid gland and undermines its ability to produce thyroid hormone. Like diabetes, this may be considered an autoimmune disease. Environmental exposure to chemicals like perchlorate, found in rocket fuel, and polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), both used as flame retardants, may have an impact on the developing thyroid gland. Some of these are pervasive environmental contaminants, so it’s plausible that they might be contributing to the prevalence of thyroid problems.
The thyroid gland is so small that it doesn’t look particularly important. It is located in the neck and weighs just a few ounces, but it has an impact on the entire body. A healthy functioning thyroid gland normally puts out two hormones: triiodothyronine, or T3, and thyroxine, known as T4. (The numbers indicate how many atoms of iodine are part of the hormone molecule.) These hormones control how every cell in the body uses energy. They also affect a cell’s response to growth hormone and other compounds, including estrogen and calcium. Because the thyroid regulates so many different activities, symptoms of thyroid problems may be vague and general. This can make diagnosis difficult.
Untreated hypothyroidism can be a very serious condition, contributing to other problems like infertility, heart disease, and depression. Getting the proper diagnosis and treatment may take some negotiating. Remember, how you feel is an important criterion for how well your treatment is going, although the blood tests are also important.
- If you have four or five of the symptoms of low thyroid activity, ask your doctor to test your thyroid function.
- Keep track of your results, especially if you have been diagnosed with hypothyroidism. You will want to follow trends and see how your treatment affects the value of TSH, T4, and T3.
- Levothyroxine is the usual treatment. Especially in older people, the starting dose should be low and gradually increased until symptoms ease and the test results normalize.
- Some people do better on one levothyroxine formulation than on another. They are considered bioequivalent, so use the one that works for you. But don’t switch back and forth between them, or between a brand name and generic. Differences in formulation can make a difference in the dose you need.
- If levothyroxine alone does not alleviate your symptoms, ask your doctor about a trial with a small amount of Armour desiccated thyroid or another source of T3. You may need to reduce the dose of levothyroxine slightly to compensate.
- T3 (Cytomel) may need to be taken two or three times a day if it is added to the regimen. It does not last long in the body.
- Don’t overdo on foods, especially soy, that interfere with thyroid peroxidase.
- Consider daily supplements of selenium (50 to 100 micrograms) and zinc (15 to 25 milligrams).
- For more information, consult Mary Shomon’s book Living Well with Hypothyroidism.