Selenium is a trace element but essential in the body.

Selenium is a trace element that is essential in small doses but toxic at high levels. Humans request selenium for the functioning of selenium dependent enzymes (silenoproteins). Plants do not require selenium for survival but when it is present in the soil, they will incorporate it into compounds usually in association with sulfur.

Selenium is an important part of antioxidant enzymes like the five glutathione peroxidases which reduce the damaging effects of reactive oxides like hydrogen peroxide by reducing them to harmless products like water and alcohols. It is also important for normal functioning of the immune system and thyroid.

There is considerable evidence that supplementation with selenium can reduce the incidences of cancer particularly prostate cancer. Also since declining selenium levels in individuals with HIV is a marker for the progressivity and severity of AIDS, some researchers believe that selenium supplementation can slow or reduce the progression of HIV.

Selenium deficiency has been associated with impaired functioning of the immune system. Also supplementation appears to stimulate the immune response even in individuals that are not selenium deficient.

The RDA for adults is 55 mcg/day. The richest sources of selenium are organ meats and seafood followed by muscle meats. Plants can be excellent sources of selenium but only when grown in selenium rich soils.



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