The study is being simultaneously released on the website of the Annals of Internal Medicine.
In animal and observational studies, vitamin E supplementation was shown to prevent cardiovascular disease and cancer. However, other studies suggested that high doses could be harmful.
To determine if there is a "dose response," researchers examined different doses of vitamin E supplements and risk of death from any cause. They studied death rates in published clinical trials comparing vitamin E supplementation to placebo and included findings from 14 studies, from 1993 to 2004. Doses ranged from 15 to 2000 IU/day, and average intake was about 400 IU a day.
"Increasing doses of vitamin E were linked to an increase in death," said lead author Edgar R. Miller, M.D., Ph.D., associate professor of medicine at Johns Hopkins University in Baltimore, Md.
According to the analysis, there is no increased risk of death with a dose of 200 IU per day or less, and there may even be some benefit. However, an increased risk was found at amounts above 200 IU per day and significant risk of death was found starting at 400 IU a day. Those who take greater than 400 IU of vitamin E a day are about 10 percent more likely to die than those who do not, researchers said. "Many people who take vitamin E supplements take between 400 and 800 IU in a single capsule," said Miller.
The confusion for many, said Miller, is that some doctors have recommended vitamin E supplementation based on studies suggesting that it is beneficial for specific illnesses. One study in people with a history of prior heart attack showed that vitamin E use correlated with a lower risk of having a second event. In another trial, patients with end-stage kidney disease
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Contact: Darcy Spitz
darcy.spitz@heart.org
212-878-5940
American Heart Association
10-Nov-2004