Vitamin E is an essential nutrient that functions as an antioxidant in the human body.
It is essential, by definition, because the body cannot manufacture its own vitamin E and thus it must be provided by foods and supplements. Vitamin E is a generic term that includes all entities that exhibit the biological activity of alpha-tocopherol. The acetate and succinate derivatives of the natural tocopherols have vitamin E activity, as do synthetic tocopherols and their acetate and succinate derivatives. Natural and synthetic vitamin E are not equivalent in composition, structure or bioavailability. However, recent human studies using deuterium-labeled vitamin E indicate that the bioavailability of natural vitamin E is approximately twice that of synthetic vitamin E, as natural vitamin E is retained longer in body tissues.