Evaluation of Selenium and Chromium Content in Selected Foods - II

Selenium was found to be an essential trace element in 1957, when it was discovered that animals deficient in selenium had increased susceptibility to liver necrosis. Foods may contain excess or deficiency of selenium, thus leading to signs of toxicity or of deficiency disease. 'Alkali disease' in cattle occurs when grains and forages containing high levels of selenium are ingested. Geological and meteorological factors determine the relative abundance of selenium in the soil in different regions of the world, giving rise to practical problems of selenium toxicity or selenium deficiency that are of considerable economic importance.