Vitamin E is a fat-soluble vitamin with antioxidant properties. Natural vitamin E exists in eight different forms: alpha, beta, gamma, and delta tocopherol; and alpha, beta, gamma, and delta tocotrienol. Alpha-tocopherol is the most active form in humans. In foods, vitamin E exists primarily as mixed tocopherols. Foods that contain vitamin E include: eggs, fortified cereals, fruit, green leafy vegetables, meat, nuts/nut oils, poultry, vegetable oils and whole grains. Vitamin E supplements are available in natural or synthetic forms. While the precise rate of vitamin E absorption is not known with certainty, it is believed to be variable and low. Reported rates of absorption of vitamin E following intake with food have varied from as high as 51%-86% to as low as 21%-29% 1. All forms of vitamin E, including all of the tocopherol and tocotrienol homologues, are absorbed through the intestine in a similar manner.
The U.S. Food and Drug Administration (FDA) has established a Reference Daily Intake (RDI) of 30 international units (IUs) vitamin E for adults and children 4 or more years of age (21CFR101.9). RDIs are a set of dietary references for essential vitamins and minerals that are considered amounts sufficient to meet the daily requirements of healthy individuals. RDIs serve as the basis for calculating the percent daily value (%DV) amounts found on dietary supplement and food labels.
Tocopherols, along with tocotrienols, are organic compounds collectively known as vitamin E. Natural tocopherols exist as a mixture of d-alpha-, d-beta-, d-gamma- and d-delta-isoforms, each having antioxidant activities 2. Tocopherols are present in many foods, such as vegetable oils, nuts and grains. They are considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) for use in foods (21CFR182.3890) 3.