This trace mineral is an important component of an enzyme that produces the thyroid hormone T3. Researchers have learned that a selenium deficiency in older adults is strongly associated with lower levels of the T3 hormone. The relationship between impaired selenium status and reduced thyroid hormone levels may be partially responsible for the hypothyroidism that’s often diagnosed in elderly women.
To keep your thyroid hormone producing enzymes working efficiently, be sure you get enough selenium each day.
Selenium for Hypothyroidism Photo Gallery
Recommended Dietary Allowance (RDA) of Selenium
AGE RDA (MICROGRAMS)
9-13 years 40 mcg
14-18 years 55 mcg
19-50 years 55 mcg
51+ years 55 mcg
Pregnancy 60 mcg
Breastfeeding 70 mcg
Reprinted with permission from Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium and Carotenoids, Copyright © 1999 by the National Academy of Sciences. Courtesy of the National Academy Press, Washington, D.C.
It’s been estimated that American women consume somewhere between 113 and 220 micrograms of selenium each day, an amount above our daily requirements. The best food sources of selenium include seafood and meat. Whole-wheat bread, wheat bran, wheat germ, oats, brown rice, Brazil nuts, Swiss chard and garlic are other good sources. Dietary intake from plant foods will vary according to the selenium content of the soil in which these foods were grown.
Women at greatest risk for a selenium deficiency are those who eat a vegetarian diet that’s based on plant foods grown in low-selenium areas. But because we eat supermarket foods that have been transported from areas throughout the United States and Canada (not to mention Mexico and South America), selenium deficiency is uncommon.
If you’re considering a supplement, check your multivitamin first. Some high-potency brands contain up to 100 micrograms of selenium. If you are buying single selenium supplements, a 200 microgram dose is plenty. You might want to choose one that contains selenomethionine or selenium-rich yeast, since these organic forms of the mineral appear to be more available to the body.
The daily upper limit for selenium for foods and supplements is 400 micrograms per day. Consuming too much selenium over a period of time has toxic effects, including hair and nail loss, gastrointestinal upset, skin rash, garlic breath odor, fatigue, irritability and nervous system abnormalities.
Iron and Iron Supplements
If you are taking Synthroid® (levothyroxine) and you are also being treated for an iron deficiency, don’t take your medication and your iron pill at the same time. It’s a good idea to take them two to three hours apart. That’s because recent experimental studies have found that iron supplements may reduce the body’s absorption of levothy-roxine. It is possible that impaired absorption of your medication could make you hypothyroid and increase your medication requirements.
If you are taking iron supplements to correct an iron deficiency, your doctor will monitor your thyroid hormone levels closely. Iron pills should be taken only if your doctor has diagnosed you with iron deficiency. If you are taking them on your own accord, be sure to let your physician know.