Vitamin E may raise death risk
Analysis finds high doses boost mortality rates
November 11, 2004
By Rob Stein
WASHINGTON - High doses of vitamin E, which millions of people take to protect themselves against heart attacks, Alzheimer's disease and other ailments, appear to increase the overall risk of dying, researchers reported.
A new analysis of data from 19 studies involving nearly 136,000 people found that beginning with the typical amount in a single vitamin E supplement capsule, the risk of death from all causes increased as the dose of vitamin E rose.
Other studies have suggested that Vitamin E might boost the risk of heart attacks and strokes, perhaps by affecting blood clotting or blocking the beneficial effects of other nutrients.
Whatever the mechanism, the findings indicate that no one should take high doses of vitamin E regularly and that guidelines for what is considered a safe maximum daily intake should be lower, the researchers said in a study presented at an American Heart Association meeting in New Orleans.
"A lot of people take vitamins because they believe it will benefit their health in the long term and prolong life," said Edgar R. Miller III, an associate professor of medicine at the Johns Hopkins University School of Medicine who led the research. "But our study shows that use of high-dose vitamin E supplements certainly did not prolong life but was associated with a higher risk of death."
The analysis is the latest in a series of recent findings undermining the theory that "antioxidant" substances may provide powerful protection against a host of illnesses. Evidence had suggested that vitamins and other compounds in many foods might reduce the risk of heart disease, cancer and other illnesses by preventing unstable oxygen molecules known as free radicals from damaging DNA.
In 2003, Americans spent $710 million on vitamin E, making it second only to vitamin C in popularity, according to the Nutrition Business Journal, which tracks industry trends.
But when researchers have attempted to give antioxidants to prevent disease, the results largely have been disappointing, and sometimes alarming. Beta carotene, for example, was found to increase rather than decrease the risk of lung cancer.
The latest study suggests that may be true for vitamin E as well, experts said.
"This just shows us once again that very high level of individual nutrients can have adverse effects," said Alice Lichtenstein, a professor of nutrition at Tufts University who chairs the nutrition committee of the American Heart Association, which in August recommended against antioxidant supplements to cut heart disease risk.
Other researchers, however, questioned the findings, saying the new analysis was flawed.
While there is only weak evidence that antioxidants reduce the risk of cancer, there is strong evidence vitamins E and C reduce the risk of heart and kidney disease, said Ishwarlal Jialal, a researcher at the University of California-Davis.
"Vitamin E is clearly an antioxidant and an anti-inflammatory agent, and it's been shown in some studies to reduce heart disease either alone or in combination with vitamin C," Jialal said.
The latest study, however, found that the overall death rate appeared to increase at a dose of 400 international units per day, Miller and his colleagues report in the January issue of the Annals of Internal Medicine.
Source:www.chron.com
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