Selenium - a fascinating antioxidant of protective properties.

Selenium is a trace element which fulfils important functions in the organism. Its deficit may cause acute disorders, but an overdose can also lead to severe consequences. The functions of selenium in the organism are mainly connected with its antioxidant properties, as it is an essential part of important antioxidant enzymes. Disturbances of oxidant balance have been found to be involved in the activity of numerous harmful factors as well as in the pathogenesis of diverse illnesses. Selenium administration has proved to be effective against the toxicity of many agents and the side effects of drugs. However, the narrow range between therapeutic and toxic doses of selenium, as well as the dependence of its effect on the applied form, dose and method of treatment, makes the choice of the most effective supplement a very complex issue. Divergent forms of selenium are still being studied, including both inorganic and organic compounds as well as Se-enriched natural products. The newest research has also involved selenium nanoparticles. The aim of this review is to present the great potential of selenium for protecting the organism against a wide variety of environmental pollutants, drugs and physical factors.