Vitamin E is a member of the family of fat-soluble antioxidant nutrients known as tocopherols. Alpha tocopherol is the most active of the tocopherols in terms of vitamin E activity, but beta, delta, and gamma tocopherols have antioxidant capabilities as well. Another closely related group of compounds, the tocotrienols also exhibit antioxidant properties. Many nutritionists recommend natural-source supplements that include a mix of tocopherols and tocotrienols, because these compounds are believed to complement each other's activity. Supplemental vitamin E is available in natural and synthetic forms, with the more potent, natural forms distinguished by a "d" (d-alpha tocopherol) while synthetic forms are indicated by "dl" (dl-alpha tocopherol).
The best food sources of vitamin E include vegetable oils, nuts, seeds, whole grains, and wheat germ. Other sources include asparagus, avocado, green leafy vegetables, and tomatoes.
Vitamin E plays many vital roles in organs and systems throughout the body, from the immune system to the brain, skin, eyes, liver, and heart. As a fat-soluble nutrient, vitamin E is incorporated into the lipid portions of cell membranes, where it helps protect these structures from free-radical induced damage. As an antioxidant, vitamin E helps protect LDL cholesterol molecules from oxidation, which is especially beneficial for cardiovascular health.
While the 15 IU per day RDA for vitamin E is sufficient to prevent overt deficiency, the most commonly recommended dose of vitamin E is 400 IU per day. Many dietary factors affect the body's vitamin E requirements. A diet high in saturated fats increases vitamin E requirements. Other nutrients like vitamin C and selenium can increase the antioxidant potential of vitamin E. Vitamin E is very safe, with adverse effects being rare even at doses as high as 3,200 IU per day.