The most important role for selenium is in the enzyme glutathione peroxidase; a potent antioxidant which protects cell membranes and red blood cells from free radical damage. Glutathione peroxidase works around cells to protect them from peroxide free radicals. Vitamin E performs a similar function from within the cells. Selenium has been shown to reduce the risk of leukemia, colon cancer, lung cancer, and cancers of the rectum and ovaries. Studies have shown that cancer patients often have low levels of selenium.
Deficiencies of selenium have been linked not only to cancer, but to infertility, muscular dystrophy, rheumatoid arthritis, and heart disease. Selenium also protects the skin from the damaging effects of Ultraviolet light.
Selenium deficiency in the soil is common and many of the food content lists will overstate their selenium content because of poor soil. Whole wheat, brown rice, and oatmeal are good sources if the soils they are grown in are rich in selenium. Meat, especially organ meat, is also a good source. Both these sources are dependent upon the soil being rich in the mineral or the animals eating plants rich in selenium. Products grown in the Southern United States as well as on both coasts have lower selenium contents than those grown in the Midwest and plains states. Seafood is also a good source of selenium. As with most minerals, refining of grains removes much of selenium from the product. Cooking also plays a detrimental role in the selenium content of foods. Vitamin C may enhance the absorption rate.
Selenium can be toxic when consumed at ten times the RDA. Symptoms might include hair loss, white streaking in fingernails, fatigue, and nausea. Doses up to three times the RDA (200-250mcg)appear to be safe.
Selenium is now available separately and in some multivitamin/mineral supplements, but usually in small amounts. The best place to find selenium is in an antioxidant formula, usually containing vitamins A, C and E.
Selenium is available in two forms. The organic form, selenomethionine, which is usually extracted from yeast or ocean plants, is more easily absorbed and raises selenium levels in the blood. The inorganic form, sodium selenite is more effective at increasing activity of the antioxidant enzyme glutathione peroxidase. The best formulas will combine the two but this may be nearly impossible to find. Finding individual supplements of each may be the only way to combine all the properties of both forms, but make sure the dosage is not too high.
