Selenium is necessary for cellular function, although large amounts are quite toxic. Selenium is an important component of certain antioxidant complexes. It is also involved with the production of thyroid hormones.
Selenium is a minor non-metallic mineral, qualified in nutrition as a trace element due to its low quantitative importance, although it is vital for the
Selenium is an essential micronutrient. It is a very important cofactor for the production of antioxidant enzymes. Selenium is also an important cofactor for the production of thyroid hormone deiodinases, which convert T4 to T3 (the active thyroid hormone).
Dietary selenium comes from nuts, cereals, meat, mushrooms, fish and eggs.