Introduction

Few, if any, of the microelements that are significant in nutrition have gone through as dramatic a role metamorphosis as has selenium. For many years selenium was considered solely from the point of view of toxicity in fact, its involvement in certain animal disease syndromes has been indirectly suggested for ages. Marco Polo referred in his journals to a poisonous plant which if eaten by horses has the effect of causing the hoofs of the animals to drop off' Polo Marsden's transl. , 1926 ....

Selenium as an Essential Nutrient

Bile Salt Fat Absorption

Nonruminants played the key role in obtaining the first evidence that selenium was important in nutrition. These animals have been used to demonstrate that selenium is indeed an essential nutrient one that must be included in the diet for supporting life. In independent discoveries in 1957, selenium was identified as the third factor vitamin E and cystine had already been identified active in preventing degeneration of the liver in rats Schwarz and Foltz, 1957 and was shown to prevent exudative...

Biochemistry of Selenium Metabolism

Although chemical characterization of the various natural states of selenium in foods and feeds has been hampered by analytical difficulties, it is apparent that this element is consumed by man and animals in several organic and inorganic forms. With the exception of indicator plants, which accumulate high concentrations of this element when grown on seleniferous soils, the selenium in crop and forage plants appears to be present mainly as an integral part of the proteins. On the other hand,...