Supplements: Selenium

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Selenium is a trace mineral found in soil and food. It is an important antioxidant, which means it helps prevent harmful chemical reactions from occurring in the body's cells. Protected cells are better able to fight off diseases, including heart disease, cancer, and disorders associated with aging.

Most of us do not get enough selenium from food. When our selenium levels are low, we run a higher risk of getting a variety of illnesses because our immune systems may be sluggish and toxins build up in the blood.

If you need to add selenium to your diet, your health care provider will probably suggest that you take a selenium supplement in combination with vitamin E. Research shows that selenium taken together with vitamin E promotes overall health and prevents or treats many diseases.


  • Selenium cures Keshan disease, a serious heart disorder common to women and children in China, where the farmland lacks minerals. However, clinical studies conclude that selenium also protects the body from more common illnesses, including the following.
  • Cancer. Selenium reduces your risk of breast, colon, liver, skin, and lung cancers. Selenium keeps tumors from growing by helping to build healthy, cancer-fighting white blood cells.
  • Heart disease. Studies show that selenium prevents heart attacks and strokes by lowering your bad (LDL) cholesterol. Selenium also keeps your arteries clear of dangerous fatty deposits, which makes it an important addition to your therapy after a heart attack.
  • Weakened immune system. Selenium helps build up white blood cells, boosting your body's ability to fight illness and infection.

Selenium also helps with the following.

  • Reproductive health, through increasing male fertility, as well as helping with proper fetal development
  • Helps the liver, thyroid, and pancreas function normally
  • Prevents premature aging, cataract formation and, possibly, sudden infant death syndrome (SIDS)
  • Treats lupus, rheumatoid arthritis, and alcoholic cirrhosis of the liver
  • Treats most skin disorders, including poor elasticity, acne, eczema, and psoriasis

Dietary Sources

Much of your selenium comes from dietary sources. Brewer's yeast and wheat germ, liver, butter, fish and shellfish, garlic, grains, sunflower seeds, and Brazil nuts are all good sources of selenium. It's also found in alfalfa, burdock root, catnip, fennel seed, ginseng, raspberry leaf, and yarrow.

Selenium is destroyed when foods are refined or processed. You should try eating a wide variety of whole, unprocessed foods. This means eating foods in their original state, not canned, frozen, or commercially prepared.

Other Forms

Your health care provider may recommend that you add selenium to your diet. You can do this by taking a vitamin-mineral supplement, a nutritional antioxidant formula, or a separate supplement. Selenium is also available in nutritional yeast.

How to Take It

  • Clinical trials suggest that you take 50 to 200 mcg of selenium daily to see real benefits.
  • Men need at least 70 mcg daily; women at least 55 mcg.
  • Pregnant and nursing mothers' needs increase to 65 to 75 mcg daily.
  • Researchers say that most of us need to take more than 100 mcg of selenium supplements daily to see improvements in disease resistance and overall health.

As with all medicines and supplements, check with a health care provider before giving selenium supplements to a child.

Take selenium with vitamin E daily for best results. Ask your health care provider to recommend an appropriate dose. (1 mg selenium daily taken with 200 IUs of vitamin E is typical.)

Do not take vitamin C with selenium because it may make the selenium less effective and, possibly, more toxic.


Selenium is usually not toxic. However, high doses (more than 1,000 mcg a day) over time may produce fatigue, arthritis, hair or fingernail loss, garlicky breath or body odor, gastrointestinal disorders, or irritability. Researchers have also discovered high levels of selenium in children with behavioral problems.

Possible Interactions

Vitamin E increases selenium's effectiveness as an antioxidant. When you take the two together, you give your cells the best protection available.

Your body has a hard time absorbing and using selenium when taken with vitamin C. To avoid this, take your vitamin and mineral supplements at different times of the day. Remember that all supplements are best absorbed when taken with a meal.

You may need a higher than usual dose of selenium if you are undergoing chemotherapy.

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Previously Published in OSA Today Reproduced by permission
Updated on: 02/01/10