Selenium in medicine and treatment

Selenium, one of non-metals, has attracted great interest among many researchers over the last years. Properties of selenium were first mentioned back in the 12th century. Selenium exists in two forms, organic and inorganic one. But whatever the form of supplementation, it is an essential micronutrient conditioning many vital functions. Large-scale research has shown that it has many important properties, including antioxidant ones, for living organisms. It is incorporated in many enzymes and proteins. Numerous studies on this element have demonstrated its beneficial effects, mainly on the cardiovascular and nervous systems. It also contributes to reduction in the incidence of many neoplastic diseases. However, despite numerous desirable effects of this element in the human body, it should be remembered that selenium is also a toxic substance with a narrow therapeutic index. Its excessive consumption contributes to the development of a condition called selenosis. The recommended dose of selenium, depending on the patient’s age, ranges from 25 to 70 μg 24 h–1. However, selenium in excess of 700 μg 24 h–1 shows strong toxicity. Therefore, adequate selenium supplementation is crucial. Nonetheless, despite numerous studies on selenium and its biological role, this trace element still raises many unresolved questions.