Vitamin E is most widely recognized for its antioxidant function that terminates the self-perpetuating cycle of lipid peroxidation. This means it protects body tissue from damage caused by substances called free radicals. Free radicals can harm cells, tissues, and organs. They are believed to play a role in certain conditions related to aging.
Tocopherols act as antioxidants by breaking free-radical chain reactions. Vitamin C helps to regenerate the active form of vitamin E. Vitamin E deficiency can result in erythrocyte fragility, muscular degeneration, steatitis, retinopathy, and reproductive failure. Vitamin E excess appears to be non-toxic.
Vitamin E also enhances immune function and prevents clots from forming in heart arteries. Vitamin E (alpha-tocopherol) has been shown to prevent oxidation of low-density lipoprotein cholesterol in vascular (endothelial) cells, nucleotides of DNA and RNA and cell membrane lipids.
Vitamin E came to public attention in the 1980s when scientists began to understand that free radical damage was involved in the early stages of artery-clogging atherosclerosis, and might also contribute to cancer, vision loss, and a host of other chronic conditions.
Vitamin E is only a minor component of the cell membrane; however, it may play a significant structural role in the plasma membrane. Vitamin E is a lipophilic molecule that partitions into hydrophobic portions of the bilayer. Once attached, the vitamin’s mobility within the membrane is impaired, and this is thought to stabilize the membrane.
Vegetable oils, such as wheat germ, sunflower, corn germ, soybean, and rapeseed, are the primary dietary source of vitamin E for humans.
Biological functions of vitamin E
