Utilization of vitamin E.
Natural (RRR) or synthetic (all-rac) forms of alpha-tocopherol are available (usually as acetate esters) for use as vitamin E supplements. In animal tests, the natural stereoisomer, RRR-alpha-tocopheryl acetate, is 1.36 times more biologically potent than all-rac-alpha-tocopheryl acetate, an equimolar mixture of eight stereoisomers [8,15,40-43]. The higher biologic activity of natural compared with synthetic vitamin E does not result from differences in antioxidant activity [2,3], but could hypothetically be explained by differences in (1) absorption, (2) plasma transport, (3) delivery to tissues, or (4) metabolism. These possibilities will be considered in this review.
Traber
M G
MG
Department of Nutrition and Food Management, Linus Pauling Institute, Oregon State University, Corvallis 97331, USA. Maret.Traber@orst.edu
D000818:Animals; D006801:Humans; D007408:Intestinal Absorption; D014018:Tissue Distribution; D014810:Vitamin E / Q000737:chemistry / Q000378:metabolism*
D014810:Vitamin E