Selenium is a constituent of most body tissues, but the heaviest concentration of the mineral is in the liver, kidneys, and heart.
Functions.Selenium is a component of an enzyme that acts as an antioxi-dant. In this way, it protects cells against oxidation and spares vitamin E.
Sources.The best sources of selenium are seafood, kidney, liver, and mus-cle meats.
Requirements.The DRI for selenium for an adult male and female is70μg.
Deficiency or Toxicity.Symptoms of selenium deficiency are unclear,but selenium supplements appear to be effective in treating Keshan disease. High doses (1 mg or more daily) are toxic and can cause vomiting, loss of hair and nails, and skin lesions.