By Adam Marcus
HealthScout Reporter

Spending a bundle on vitamin E supplements to ward off the perils of oxidation? A new study suggests that you shouldn't bother if you're healthy.

The study, which underscores the seesaw nature of nutritional supplement research, says high doses of vitamin E do not appear to help clear the body of potentially harmful antioxidants linked to blood vessel damage.

Previous studies had suggested that vitamin E might help protect blood vessels, brain cells, and other body parts from free radicals, normal byproducts of oxidation reactions in metabolism, which play a role in everything from heart disease to Alzheimer's. Yet other studies haven't found such effects, leaving researchers and patients in a muddle of conflicting data.

Now, researchers report that even extremely high doses of vitamin E do not improve several key markers of antioxidant damage to fat molecules, at least in healthy people. The findings, reported in the March 7 issue of the Journal of the American Medical Association, suggest that most Americans likely get the full benefit of vitamin E from their diets through foods like milk, leafy vegetables, vegetable oils and eggs.

"Vitamin E is an antioxidant; it has that capacity," says Dr. Ronald Krauss, head of molecular medicine at Lawrence Berkeley National Laboratory at the University of California at Berkeley, who is familiar with the research. However, Krauss says, "This study, which wasn't huge, failed to see a significant effect" of the nutrient on chemical signs of fat breakdown that might precipitate blood vessel disease.

The work doesn't speak to whether vitamin E supplements might protect people with established cardiovascular problems, Krauss says, but "there is really not a consistent story, and several of the better studies have shown no benefit" of the antioxidant for these patients.

The research team, led by Dr. Emma Meagher of the University of Pennsylvania, looked for the effects of varying doses of vitamin E on three important measures of antioxidant damage of fat.

Fats, or lipids, are families of molecules that, among other things, make up essential mortar in cell membranes that shield the interior from external hazards.

The latest study included 30 healthy subjects, ages 18 to 60, who were not taking vitamin pills and had normal blood levels of vitamin E consumed in food. For eight weeks, participants took supplements of alpha-tocopherol, in doses ranging from a modest 200 international units to a whopping 2,000 international units. Others were given sugar pills.

No matter the dose, subjects who took vitamin E showed no differences from subjects taking placebos in markers of lipid peroxidation excreted in their urine.

"Our results question the potential benefit of the reportedly widespread consumption of vitamin E" by healthy people, write the authors.

Dr. Allan Butterfield, an expert in oxidation stress at the University of Kentucky in Lexington, says changes in fats are a useful marker for the effects of an antioxidant like vitamin E, but they're not the only one. Therefore, Butterfield says vitamin E still might help prevent free radical damage of other important molecules, such as proteins or DNA.

What To Do

This study isn't huge, and it won't be the last word on vitamin E supplements.

Men should get 10 milligrams of vitamin E a day, while 8 milligrams is adequate for women. Taking substantially more is not thought to be harmful, though, as the latest work shows, it's not likely to help healthy people. Visit Ask the Dietician to learn about sources of vitamin E and try the American Dietetic Association for information about antioxidants.

To learn more about vitamin E's role in cardiovascular disease, try the Heart Information Network.

For a somewhat more skeptical look at antioxidants, check Quackwatch.