Selenium:

Selenium is an essential mineral that possesses strong antioxidant properties. It's primary role in the human body is as a component of glutathione peroxidase, an antioxidant enzyme that protects blood cells from the ravages of highly reactive oxygen compounds called free-radicals. Working synergistically with vitamin E, another potent antioxidant, selenium aids in the production of antibodies, and in protecting the immune system. Selenium is required to maintain tissue elasticity, and to support the healthy functioning of the pancreas and the heart. Children suffering from Keshan's disease, a rare heart disorder, respond well to selenium supplements, as may many adults suffering from a common form of heart disease called cardiomyopathy.

A deficiency of this vital trace element has been linked to the development of leukemia, rheumatoid arthritis, and fibrocystic breast disease. Researchers have also found that the lower the concentration of selenium in the blood stream, the higher the risk of developing cancers of the breast, lungs, ovaries, pancreas, cervix, uterus, colon and rectum. Children with Down's Syndrome also evidence lower serum levels of selenium which is thought to result in increased free radical damage to the nerves.

The Recommended Daily Intake of selenium is 10 micrograms for infants, 70 micrograms for adults, and 75 micrograms for lactating women. Foods high in selenium include meats, seafood, brewer's yeast, broccoli, grains, chicken, garlic and onions. Selenium can be toxic in amounts as little as 750 micrograms per day, causing the loss of teeth and hair, painful swelling of the fingers, fatigue, nausea, and vomiting.