What Is In Selenium Supplements?

Selenium supplements usually contain the type of selenium that occurs naturally in staple foods such as corn, wheat, and soybeans. In these foods, selenium is present as selenomethionine, the organic selenium analogue of the amino acid methionine. Selenomethionine can be incorporated into body proteins in place of methionine, and is the form in which selenium is stored in organs and tissues.

Selenium supplements may also contain sodium selenite and sodium selenate, two inorganic forms of selenium. Selenomethionine is generally considered to be the best absorbed and utilized form of selenium.

Selenium is also available in 'high selenium yeasts', which may contain as much as 1,000 to 2,000 micrograms of selenium per gram. Most of the selenium in these yeasts is in the form of selenomethionine. This form of selenium was used in the large scale cancer prevention trial in 1983, which demonstrated that taking a daily supplement containing 200 micrograms of selenium per day could lower the risk of developing prostate, lung, and colorectal cancer.