Define about the Metabolism of Selenium compounds?

Selenium compounds' are generally very efficiently absorbed by humans and selenium absorption does not appear to be' under homeostatic control selenium is mainly absorbed from the duodenum. Less absorption occurs in the jejunum and ileum. Inorganic forms of selenium (mainly selenate) are passively transported whereas organic forms are actively transported. Almost 5040% of dietary selenium is absorbed, with efficiency being higher for organic forms, as compared to inorganic.

Among the organic forms, selenomethionine is better absorbed than selenocysteine. Among the inorganic forms, selenales are better absorbed than selenites. For example, absorption of the selenite form of selenium is greater than 80% whereas that of selenium as selenomethionine or as selenate may be greater than 90%. In addition, some dietary factors appear to influence the absorption of the element. Phytates and heavy metals, such as mercury through chelation and precipitation, hinder selenium absorption. Vitamins C, A and E, as well as, glutathione enhance the absorption.