If selenium is present in the composition of most food supplements, it is not by chance. As a trace element, that is, as a trace mineral in the body, it is vital to many physiological processes.
Selenium is essential to the functioning of a group of enzymes, selenoproteins. The best known of these enzymes is glutathione peroxidase (GPx), which is part of the antioxidant defence system of the body. This is why selenium plays a determining role in activating the defence reactions of the body and in protecting cells against oxidative stress.