College of Public Health and Human Sciences

Vitamin E, a fat-soluble antioxidant, is required from the diet but amounts in excess of requirements have not been demonstrated to decrease chronic disease risk. Vitamin E is a chain-breaking, peroxyl radical scavenger that halts lipid peroxidation and protects polyunsaturated fatty acids. This antioxidant activity serves to protect the nervous system in the developing embryo, in sensory neurons in children and adults. Plants synthesize eight vitamin E forms, but only one, α-tocopherol, meets human requirements. Two physiologic functions maintain the preference for α-tocopherol in the human body. These are (1) the preferential secretion of α-tocopherol into the plasma, facilitated by the hepatic α-tocopherol transfer protein and (2) vitamin E metabolism, which promotes non-α-tocopherol and “excess” α-tocopherol excretion from the body.