Peer Reviewed

Selenium SymbolSelenium is a metalloid element of sulfur found in the soil and food. It naturally occurs in iron, nickel ores, copper, and lead. It is a vital antioxidant.

When combined with Vitamin E, selenium's antioxidant properties (anti-aging) protect the immune system by eradicating free radicals. It may prevent the formation of certain cancerous tumors (eg, breast, colon, liver), and heart disease (lowers bad cholesterol—LDL). It may help improve skin disorders (poor elasticity, acne, psoriasis), and plays a part in protecting the liver (alcoholic cirrhosis), thyroid, and pancreas.

Selenium deficiency may present the following symptoms:

  • Growth impairment
  • Exhaustion
  • Heart disease
  • Sterility
  • High cholesterol levels
  • Liver/pancreatic impairment

Sources of Selenium
Selenium is found in Brazil nuts, Brewer's yeast, wheat germ, chicken, whole grains, dairy products, tuna, vegetables, seafood, broccoli, and brown rice. Many herbs contain selenium, such as rose hips, yellow dock, cayenne, alfalfa, catnip, and fennel seed.

Purchase foods that are not processed. Processing destroys selenium. Avoid frozen, canned, or prepared foods.

Many multivitamin formulas contain selenium. It is also found in antioxidant formulas, nutritional yeast, and individually.

Guidelines and Cautions
Sources suggest the following daily doses: men 70 micrograms (mcg), women 55 mcg, and pregnant/nursing women 65 to 75 mcg.

  • The effects of selenium are enhanced with Vitamin E.
  • Vitamin C robs the effectiveness of selenium when combined.
  • Unless your health care provider prescribes it, do not take more than 400 mcg daily. Because one ounce of Brazil nuts can contain as much as 544 mcg of selenium, do not consume these nuts if you take supplemental selenium.
  • If you are pregnant, do not take more than 40 mcg of supplemental selenium daily, and do not consume Brazil nuts.

High selenium levels may present the following symptoms: arthritis, hair loss, irritability, yellowish skin, bad breath (garlic), metallic taste, and brittle nails.

Disclaimer: Many people report feeling improvement in their condition and/or general well-being taking dietary, vitamin, mineral, and/or herbal supplements. The Editorial Board of, however, cannot endorse such products since most lack peer-reviewed scientific validation of their claims. In most cases an appropriate diet and a "multiple vitamin" will provide the necessary dietary supplements for most individuals. Prior to taking additional dietary, vitamin, mineral, and/or herbal supplements it is recommended that patients consult with their personal physician to discuss their specific supplement requirements.

Updated on: 03/16/16
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Mark R. McLaughlin, MD
While I have had some patients that describe improvement of their symptoms from various dietary supplements, there is little scientific evidence that they work. In small amounts, I do not believe they are harmful, but I am not convinced they are any more effective than adhering to a healthy, well-balanced diet. On the contrary, there is strong scientific evidence showing that patients with a poor overall nutritional status have higher complication rates from surgery.
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