High doses of vitamin E, often viewed as a panacea for cancer, heart disease and other illnesses, actually increase the risk of death slightly among the elderly and infirm, researchers said Wednesday.
A study found that the increased risk of death was small, about 5% for those who had taken larger doses of the vitamin for at least five years. But vitamin E is taken by so many people -- an estimated 25% of the American population -- that even a small increase is significant, the researchers said.
“People take vitamins because they believe it will benefit their health in the long term and prolong life,” said Dr. Edgar R. Miller III of the Johns Hopkins University School of Medicine, a coauthor of the study. “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.”
Miller presented the results Wednesday at a New Orleans meeting of the American Heart Assn., and they were simultaneously published online in the Archives of Internal Medicine.
“Too often, in terms of the supplements, there’s very scant science,” Dr. Raymond Gibbons of the Mayo Clinic told a news conference at the heart meeting. “In this area, we have the science: Vitamin E doesn’t work.”
But some scientists were skeptical of the results.
Dr. David Heber, director of the UCLA Center for Human Nutrition, noted that there was “a disconnect” between large studies like this one and smaller studies that had shown a benefit from taking vitamin E.
Many of the people in the studies “were older people and had preexisting diseases. It’s hard to ascribe the bad outcomes to vitamin E, per se,” Heber said.
The results came from a so-called meta-analysis that combined data on 135,967 patients in 19 separate studies. The combined results indicated an increased risk for patients -- most of whom were over the age of 60 and suffering from heart disease or other illnesses -- who took more than 400 international units, or IU, of vitamin E each day.
The results said nothing about the effects of high doses in older people who were healthy or the effects in younger people. The study found no increased risk at doses below 200 IU, and possibly a slight benefit.
The typical vitamin E supplement contains 400 IU, although some contain as much as 1,000. Multivitamin supplements typically contain 30 to 60 IU.
Most people get about 6 to 10 IU of vitamin E per day from their diet, typically from vegetable oils, green leafy vegetables, seeds, nuts and corn.
Many people take supplements of the vitamin because it is an antioxidant that is thought to destroy oxygen radicals produced by chemical reactions gone awry within cells. Nutritional guidelines do not recommend vitamin E supplements and suggest a maximum daily dose of 1,500 IU.
Although the mechanism by which high doses of the supplement might cause damage is not clear, Miller speculated that the vitamin could suppress natural enzymes in the liver and increase the risk of bleeding.
Many cardiologists, as well as the American Heart Assn., recommend that patients not take vitamin E because previous studies have shown the supplements are not beneficial. The new findings seem likely to increase the urgency of such warnings.
Vitamin E manufacturers and proponents scoffed at the results.
John Hathcock, vice president of scientific affairs for the Council for Responsible Nutrition, a supplement industry group, said the increased risk found by the study was “driven by the results from just a few of these clinical trials, some of which are suspect and/or outdated.”
“This is an unfortunate misdirection of science ... for the sake of headlines,” he said.
Leiner Health Products of Carson, which manufactures more than half of the private label vitamin E sold in the United States, dismissed the study as “scientific folly.”
Leiner spokeswoman Crystal Wright said the company was “pretty dismayed that a reputable university like Johns Hopkins would come out with something so misguided.... It scares people away from a vitamin that offers so many benefits for so many people.”