All mineral elements have their place in nature as macroelements, microelements and submicroelements. They should be delivered to the organism in the proper composition and amount and in the form easy assimilated by the organism. Creating the food composition we should take into account not only energy metabolism and digestible protein content, but also the content of minerals components, among them of selenium. Selenium is assimilated by the organism in the form of selenomethionine and selenocysteine as well as certain inorganic compounds. This element in the excess is a poison, but on the other hand it is essential food component, because of its roles in the metabolism, as well as anticancer factor and antioxidant.