Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
A PRÉCIS ON SELENIUM By: Theodore Hersh, M.D.,AGAF, MACG Copyright Selenium is a vital trace element required by our body for many physiologic, enzymatic and antioxidant functions. It is derived mainly from our diet but because selenium sources in foodstuffs are often low particularly in countries with deficient selenium content in the oil, our intakes of selenium may need to be increased from dietary supplements. Plants, grasses and cereal grains take up selenium from the soil as inorganic salts (selenites and selenates) and convert these first to selenium salts and then to organic compounds, mainly as selenomethionine. Animals then obtain their selenium in the form of selenomethionine provided from the plant sources that animals consume as well as additionally from commercial animal feed supplements. Our human body’s sources of selenium from plants and animal food sources are thus derived from the gastro-intestinal absorption as selenomethionine which then may be incorporated into a number of proteins. Selenomethionine also acts itself as an antioxidant. Selenium induces the production of a number of critical enzymes, which use selenium as a cofactor in their specific physiologic functions. Notable examples include the ubiquitous enzyme glutathione peroxidase, which with the antioxidant glutathione, hydrolyzes the toxic hydrogen peroxide and renders it non-toxic. The selenoenzyme thioredoxin reductase also works synergistically with glutathione to regenerate the oxidized vitamin C molecule (dehydroascorbate) back to ascorbic acid, the antioxidant form of vitamin C. Selenium also spares vitamins C and E by preventing their auto-oxidation in the cell. When the antioxidant selenomethionine neutralizes a free radical, it too is oxidized to a selenoxide molecule. It then requires the body’s prime antioxidant, L-glutathione, to reduce and thereby recycle that molecule back to the antioxidant selenomethionine. Thus, selenium and glutathione are intimately involved in the antioxidant-reduction reactions neutralizing free radical species and regenerating spent antioxidant vitamins C and E. The glutathione and selenium complex is the cell’s primary defender against the ravages of oxidant damage and thereby helps prevent free radical diseases. Thione International, Inc. • Atlanta, GA 30305-2700, USA T: (404) 846-9331 • F: (404) 266-1605 • www.thione.com