RESUMO
Selenium is an essential trace element for humans and animals, and selenium deficiency is associated with several disease conditions such as immune impairment. Free radicals are produced in the body as a result of many biochemical processes in the body. All aerobic organisms possess antioxidant defense system to combat oxidative stress. Selenium is an important constituent of antioxidant enzymes, especially, glutathione peroxidase and some other selenoproteins that participate in various physiological activities and protects the cell against the deleterious effects of free radicals by modulating the cell response. However, their exact role is still unknown. Moreover, many human diseases are related to the cell cycle regulation. Selenium intakes, greater than the recommended daily allowance [RDA], appear to protect against certain types of cancers by finding its role in regulation of cell proliferation and apoptosis. The role of selenium has been explored in normal thyroid functioning, enhancing immune function, carcinogenesis, cardiovascular diseases, in the prevention of pre-eclampsia, diabetes mellitus and male reproduction etc. This article reviews introductory aspects of selenium as an essential micronutrient, different sources of selenium, Pharmacokinetics and its role in various pathologies and aims to provide an update on selenium profile