Vitamin E is an important fat-soluble vitamin best known for its role as an antioxidant, fighting off reactive free radicals that damage cells. While you should get adequate amounts of naturally occurring vitamin E from your diet, in some cases you may need to take an over-the-counter supplement that provides natural or synthetic vitamin E. If you decide to take a supplement, let your physician know ahead of time to avoid any adverse reactions with other nutrients or medications.
Forms of Vitamin E
Vitamin E includes a group of eight different antioxidants, four of which are in the form of tocopherols, either alpha, beta, gamma or delta. The remaining four are tocotrienols, which also come in alpha, beta, gamma or delta variations. Alpha-tocopherol has the highest amount of biological activity in humans and is the type of vitamin E that has the largest levels in your blood. Additionally, alpha-tocopherol is the only variety of the vitamin that meets the recommended dietary allowance, or RDA, due to its high activity level in your body.
Identifying Natural vs. Synthetic E
While reading the nutrition facts label on your supplement, watch for the terms d-alpha tocopheryl succinate, d-alpha tocopherol, d-alpha tocopheryl acetate or other forms of alpha-tocopheryl. When the vitamin E is in a natural state, you will see "d" or "RRR" ahead of the complete term, but in synthetic forms the label will read "dl" or "all-rac." For example, if your multivitamin lists "dl-alpha tocopherol" or "all-rac-alpha tocopherol," you know this is the synthetic form of the nutrient.
What Constitutes Synthetic E
Natural vitamin E has only one isomer. Synthetic vitamin E undergoes esterification, in which eight isomers form. Only one of the isomers is identical to natural vitamin E, while the remaining seven isomers vary in potency and in ability to have biochemical reactions similar to those of naturally occurring isomers. According to the Linus Pauling Institute, synthetic forms of vitamin E only have about half of the biological activity of natural vitamin E.
RDA of Vitamin E
The recommended intake of natural d-alpha tocopherol or RRR-alpha tocopherol for adults is 15 mg or 22.4 IU daily, the Office of Dietary Supplements reports. Since biological activity in synthetic forms varies, read the nutrition facts label to determine how much of the synthetic form is bioavailable. You can get all of the natural alpha-tocopherol you need by filling your diet with soybean oil, peanuts, corn oil, avocados, wheat germ, sunflower seeds and almonds. These foods are excellent sources of naturally occurring vitamin E.
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