ABSTRACT
References................................................................................................................29
Because tocopherols and tocotrienols exhibit the biological activity of
α
-tocopherol, they belong to the group of compounds called vitamin E (VERIS, 1998). It was first discovered as a factor present in, for example, cereal grains to prevent reproductive failure in the rat, nutritional muscular dystrophy in the quinea pig and rabbit, and later other vitamin E deficiency symptoms. There is no specific reaction for which vitamin E is a cofactor. Instead, its role is to prevent a range of oxidation reactions of polyunsaturated lipids
in vivo
and to function as a biological antioxidant (Machlin, 1991; Combs, 1998; Traber, 1999). In the human body, vitamin E is the most important lipid-soluble antioxidant that provides an effective protective network against oxidative stress together with other antioxidants, such as vitamin C. For healthy people, it is relatively easy to get enough tocopherols and tocotrienols from the diet to prevent vitamin E deficiency, but higher daily intakes may provide other beneficial effects and may be needed when the diet contains large amounts of polyunsaturated fats (Horwitt, 1991).
