#nutrient

Vitamin A was the first fat-soluble vitamin to be recognized. Formerly known as the 'anti-infective vitamin', vitamin A has recently been recognized as a critical component of the immune system. Carotenes, some of which can be converted to vitamin A, are also getting a great deal of attention for their ability to boost the immune system. Because of the vitamin A-like activity of some carotenes, both vitamin A and carotenes are examined in this chapter.