Vitamin E refers a group of fat soluble chemicals. While there are several forms, alpha- tocopherol is the form that the body recognizes as a nutrient. It is an important antioxidant to reduce the damage caused by free radicals and it is thought to help strengthen the immune system, blood, and cell membranes.
When listed on Supplement Facts labels, vitamin E is indicated by IU, which is International Units. This is a measurement indicating biological activity, not an actual measurement of the amount of vitamin E, which differs from when it is listed in milligrams (mg). The Food and Drug Administration does not require food labels to indicate the amount of vitamin E. The recommended dietary allowance (RDA) is 15 mg (22.4 IU) to 19 mg (28.4 IU). Most multivitamins have 22 to 38 IU. Supplements indicated as ‘Vitamin E’ will have as much as 400 IU. Vitamin E also comes in both natural and synthetic forms. The synthetic form is indicated as dl-alpha- tocopherol. No harm in ingesting the synthetic form, but it is thought not to be absorbed or utilized as readily as the natural, which is indicated as d-alpha-tocopherol (acetate or succinate).
Dietary Sources of Vitamin E
Keep in mind that alpha-tocopherol is fat soluble indicating that dietary fats are a good source. Foods such as vegetable oils like olive, corn, and safflower oils, as well as the oils in nuts, seeds, and wheat germ. Almonds and sunflower seeds are known as sources high in vitamin E.
Vitamin E and Eye Health
The role vitamin E plays in the eye is one of protection as an antioxidant and support for nerve health. It was a part of the Age-Related Eye Disease Study (AREDS), which evaluated the effect of supplementing with vitamin C, E (400 IU/day), zinc, lutein, and zeaxanthin on the progression of age-related macular degeneration and cataracts. The progression of AMD was decreased by 25% with this combination of supplements. The thought is that AMD is, in part, a result of poor nutrition. (Read more about macular degeneration and vitamin supplements.)
Vitamin E Supplementation
Those who should be cautious about supplementing their dietary intake with vitamin E supplements are those who receive treatments or medications which cause blood thinning,
as high doses of vitamin E cam exacerbate blood thinning:
Anticoagulant and antiplatelet medications
Simvastatin and niacin
Chemotherapy and radiotherapy