Although it is toxic in large doses,<unk>  is an essential micronutrient for animals. In plants, it sometimes occurs in toxic amounts as forage, e.g. locoweed.<unk>  is a component of the amino acids selenocysteine and selenomethionine. In humans,<unk>  is a trace element nutrient that functions as cofactor for glutathione peroxidases and certain forms of thioredoxin reductase.<unk> -containing proteins are produced from inorganic<unk>  via the intermediacy of selenophosphate (PSeO33−).
Selenium in biology
Iodine in biology
Biological aspects of fluorine
Fatty acid ratio in food
Nutrient
Hematogen
Electrolyte
Ultraviolet index