Vitamin E:

Also Known As
Tocopherol, tocopheryl (acetate, succinate, etc.)

Physiology and Clinical Effects
Vitamin E is a powerful antioxidant that protects cell membranes and other fat-soluble parts of the body, such as LDL cholesterol (the “bad” cholesterol). Protection of LDL cholesterol may reduce the risk of heart disease. Two studies published in the New England Journal of Medicine show that both men¹ and women² who supplement with at least 100 IU of vitamin E per day for at least two years have a 37–41% drop in the risk of heart disease. Even more impressive is the 77% drop in nonfatal heart attacks reported in the double-blind CHAOS study, in which people were given 400–800 IU vitamin E per day.³

What About The Different Kinds Of Vitamin E?
The names of all types of vitamin E begin with either “d” or “dl,” which refer to differences in chemical structure. The “d” form is natural and “dl” is synthetic. The natural form is more active. More synthetic vitamin E is added to supplements to compensate for the low level of activity. For example, 100 IU of vitamin E requires about 67 mg of the natural form but at least 100 mg of the synthetic. Little is known about how the synthetic “dl” form affects the body, though no clear toxicity has been discovered. Many doctors advise people to use only the natural (“d”) form of vitamin E.

After the “d” or “dl” designation, often the Greek letter “alpha” appears, which also describes the structure. Synthetic “dl” vitamin E is found only in the alpha form—as in “dl-alpha tocopherol.” Natural vitamin E can be found either as alpha—as in “d-alpha tocopherol”—or in combination with beta, gamma, and delta—this combination is labeled “mixed” (as in mixed natural tocopherols).

Human trials with vitamin E have almost always been done with the alpha (not gamma) form. Historically the synthetic “dl” form was used in most trials, but some trials are now using the natural form. The two reports mentioned above (men and women who supplement vitamin E have fewer heart attacks) measured alpha intake. The double-blind CHAOS trial mentioned above, showing a 77% reduction in nonfatal attacks, used alpha and not gamma. This strongly suggests that the alpha form is protective.

A group of researchers recently claimed that gamma might better protect against oxidative damage;⁴ the evidence comes from a test tube study. As a result, some have hypothesized that alpha might interfere with the activity of gamma-tocopherol, a claim that remains unproven.

The issue of alpha versus gamma requires much more research before it can be fully understood. Almost all vitamin E research shows that positive results require hundreds of units per day—an amount easily obtained with supplements but impossible with food. Therefore, switching to food sources as suggested by some researchers is impractical. Until more is known, people seeking to add gamma tocopherol can find mixed natural tocopherol supplements. They contain a small amount of gamma, but the percentage remains much lower than that found in food.

Vitamin E forms are listed as either “tocopherol” or “tocopheryl” followed by the name of what is attached to it, as in “tocopheryl acetate.” The two forms are not greatly different; however, tocopherol may absorb a little better, while tocopheryl forms may have slightly better shelf life. Both forms are active when taken per os. However, the skin cannot utilize the tocopheryl forms, so those planning to apply vitamin E to the skin should buy tocopherol. In health food stores, the most common forms of vitamin E are d-alpha tocopherol and d-alpha tocopheryl (acetate or succinate). Both of these d (natural) alpha forms are frequently recommended by doctors.

Food Sources
Wheat germ oil, nuts, seeds, vegetable oils, whole grains, egg yolks, and leafy green vegetables all contain vitamin E. However, the high levels found in supplements, often 100–800 IU per day, are not obtainable from eating food.

Deficiency Risk and Symptoms
Severe vitamin E deficiencies are rare.

Recommended Dosage
The most commonly recommended dose of vitamin E for adults is 400–800 IU per day. However, some leading researchers suggest taking only 100–200 IU per day as studies that have explored the long-term effects of different supplemental levels suggest no further benefit beyond that amount. In addition, research reporting positive effects with 400–800 IU per day have not investigated the effects of lower intakes.⁵

Contraindications
Vitamin E toxicity is very rare; supplements are widely considered to be safe.

A diet high in unsaturated fat increases vitamin E requirements. Vitamin E and selenium work together to protect fat-soluble parts of the body.

References:

1. Rimm EB, Stampfer MJ, Ascherio A, et al. Vitamin E consumption and the risk of coronary heart disease in men. N Engl J Med 1993;328:1450–6.
2. Stampfer MJ, Hennekens CH, Manson JE, et al. Vitamin E consumption and the risk of coronary heart disease in women. N Engl J Med 1993;328:1444–9.
3. Stephens NG, Parsons A, Schofield PM, et al. Randomised controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study (CHAOS). Lancet 1996;347:781–6.
4. Christen S, Woodall AA, Shigenaga MK, Southwell-Keely, Duncan MW, Ames BN. Gamma-tocopherol traps mutagenic electrophiles such as NO+ and complements alpha-tocopherol: physiological implications. Proc Natl Acad Sci 1997;94:3217–22.
5. Rimm E. Micronutrients, Coronary Heart disease and cancer: Should we all be on supplements? Presented at the 60th Annual Biology Colloquium, Oregon State University, February 25, 1999.

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