Selenomethionine

Figure 1. The chemical structure of Selenomethionine.

Selenomethionine is a naturally occurring amino acid. The L-selenomethionine enantiomer is the main form of Selenium found in Brazil nuts, cereal grains, soybeans, and grassland legumes, while Se-methylselenocysteine, or its gamma-glutamyl derivative, is the major form of selenium found in Astragalus, Allium, and Brassica species.

In the human body, Selenomethionine functions as an antioxidant. Selenomethionine's antioxidant activity arises from its ability to deplete reactive oxygen species readily. Selenium and methionine also play separate roles in the formation and recycling of glutathione, a key endogenous antioxidant in the human body.

Selenomethionine is readily available as a dietary supplement. As an organic form of Selenium, Selenomethionine may be easier for the human body to absorb than selenite, which is an inorganic form of Selenium.

For nutritional values, refer to the Codex entry for Selenium.