[Selenium: current epidemiological and physiopathological findings. Status in Belgium].

Selenium is an essential trace element involved in the "protection" of organism by its constitution of the active site of the enzyme glutathion peroxydase and its participation in functions such as biotransformation, detoxification and immune response. Functional and clinical consequences of selenium deficiency have been largely described as well as requirements that depend on several "aggression" factors. Further studies are however necessary to demonstrate its activity in the prevention of some chronic diseases.