"I think people take vitamin E because they think it is going to make you live longer, but this (study) doesn't support that," Miller told reporters.

Miller and colleagues re-analyzed 19 studies of vitamin E and health between 1993 and 2004. The trials involved more than 136,000 mostly elderly patients in North America, Europe and China.

People who took 200 international units of vitamin E a day or more died at a higher rate during the study, which lasted three years, than people who did not take supplements, they told a meeting of the American Heart Association.

"It's about a 5 percent increased risk at 45 years in the trials pooled together," Miller said.

"That doesn't sound like a lot but if you apply it to 25 percent of the (U.S.) adult population taking vitamin E, that is significant."

Miller, whose findings are also being published online by the Annals of Internal Medicine, said two-thirds of people who take vitamin E supplements take 400 IU or more.

"We don't think that people need to take vitamin E supplements, that they get enough from the diet," he said. Nuts, oils, whole grains and green leafy vegetables are all rich in vitamin E.

MUCH MORE THAN NEEDED

The average U.S. diet supplies six to 10 IU of E, Miller said. The Institute of Medicine, which sets recommended doses of vitamins and minerals, gives 1,500 IU of E as a daily upper limit.

"I would say it is too high," Miller said. The U.S. government's Food and Drug Administration is barred by law from regulating dietary supplements so the limits are voluntary.

People take large doses of vitamin E in the belief that it helps counter oxidation by unstable "free radical" molecules, which damages cells and can accelerate aging and lead to heart disease and cancer.

Miller, who was surprised by the findings of the study, said there could be several ways the vitamin supplementation is damaging the body.

While vitamin E in low doses is a powerful antioxidant, in higher doses its effects may promote oxidative damage, and may also overwhelm the body's natural antioxidants, he said.

Dr. Raymond Gibbons of the Mayo Clinic in Rochester, Minnesota, said the evidence has been building against vitamin E supplements.

"Despite this ... I see many, many patients still taking vitamin E and I have to convince them not to," he told a separate news conference.

But the Council for Responsible Nutrition, a trade group for supplement makers, criticized the report.

"This is an unfortunate misdirection of science in an attempt to make something out of nothing for the sake of headlines," said the group's John Hathcock.