Selenium exists in all body cells and is a central component in the formation of selenium-dependent enzymes which fulfil important functions in the body.
Selenoenzymes are active in terms of cell protection and the capture of free radicals. Selenium contributes to the protection of important cell components, such as the genetic information, from oxidative damage. Selenium is important for the normal function of the immune system since it is incorporated into anti-inflammatory and antioxidant protective systems which are part of the immune system.
Moreover, a sufficient supply with selenium supports the thyroid in its normal function. Because selenium does not only accept cell-protecting tasks in the thyroid but is involved the activation and inactivation of the thyroid hormones which in turn are necessary for a multitude of processes in the body. The hormones of the thyroid are e.g. responsible for the warmth regulation, energy metabolism, basal metabolic rate, cardiovascular activity, muscle function, psyche and reproduction capability.
Likewise, selenium is necessary for the normal production of sperm and for the maintenance of normal hair and nails because selenium is e.g. involved in the the cell cycle of the hair follicle and thus, in the maintenance of normal hair growth.