High Doses of Vitamin E Could Lead to Increased Risk for Death, Study Finds
Taking a dose of more than 400 international units of vitamin E per day can lead to an increased risk of death, according to a study presented on Wednesday at the American Heart Association's annual conference and published online in the Annals of Internal Medicine, USA Today reports. Results for the study -- led by Edgar Miller, an associate professor of medicine and epidemiology at Johns Hopkins University -- were complied from an analysis of 135,967 people enrolled in 19 separate studies conducted between 1993 and 2004 (Sternberg, USA Today, 11/11). Most enrollees were over age 60 and had chronic diseases (Maugh/Reitman, Los Angeles Times, 11/11).
The study found that for those taking 400 IU -- a "common dose" -- or more of vitamin E per day, there were 39 additional deaths per 10,000 people, according to the Knight Ridder/Baltimore Sun. Among those taking less than 400 IU per day, there were 16 fewer deaths per 10,000. The benefit "became significant" in doses less than 150 IU per day, the study found, according to the Knight Ridder/Sun.
Miller said high doses of vitamin E might inhibit other antioxidants or possibly reduce clotting to the extent that a patient could be at higher risk for stroke (Fauber, Knight Ridder/Baltimore Sun, 11/11). Miller also said the vitamin could be causing a suppression of enzymes in the liver, increasing risk of bleeding, the Los Angeles Times reports (Los Angeles Times, 11/11).
Federal guidelines do not recommend vitamin E but state that doses up to 1,000 IU daily are safe; Miller and his researchers suggested that the limit should be reevaluated in light of their findings (Stein, Washington Post, 11/11). The researchers warned that because most of the studies involved patients with chronic diseases, "it is difficult to generalize the findings to healthy adults," USA Today reports (USA Today, 11/11).
Although the increased risk of death is small, it could be significant because an estimated 25% of the U.S. population takes vitamin E supplements, of which about two-thirds are high doses (USA Today, 11/11). Benjamin Caballero, director of the Center for Human Nutrition at Johns Hopkins Bloomberg School of Public Health, said, "This reaffirms what many have already said. The evidence for supplementing with any vitamin, and particularly vitamin E, is just not there. This idea that people have that even if it does not have any effect, at least it will not hurt, may not be that simple."
James Robins, a Harvard University statistician, said, "They may be right but they somewhat oversold it statistically. It is definitely true that there is no evidence that the low dose does anything for you, and a high dose may be bad. I wouldn't tell anyone to take this stuff, but this is hardly definitive evidence" (Kolata, New York Times, 11/11).
John Hathcock, vice president of scientific affairs for the supplement-industry group Council for Responsible Nutrition, said the study was "driven by the results from just a few of these clinical trials, some of which are suspect and/or outdated."
David Heber, director of the UCLA Center for Human Nutrition, said there was a "disconnect" between Miller's study and smaller studies that showed a benefit from taking vitamin E. Heber said that since many of the participants in the study "were older people and had preexisting diseases, [i]t's hard to ascribe the bad outcomes to vitamin E, per se" (Los Angeles Times, 11/11). The study is available online.