Jan. 25, 2000 (New York) -- Despite favorable animal studies and some inconclusive evidence in people, a study in the Jan. 20 issue of The New England Journal of Medicine suggests that taking vitamin E supplements every day for over four years does not reduce the risk of death or heart attack in people with heart disease or diabetes.
In several studies, fruits, vegetables, and other foods containing antioxidant vitamins such as vitamin E have been associated with a reduction in the risk of heart disease and levels of 'bad' LDL cholesterol. Antioxidants prevent the formation of free radicals that cause disease.
However, the new study found no significant differences in deaths from heart disease or stroke, or in the incidence of second heart attacks or death from any cause, in men and women aged 55 or older who were randomly assigned to take either vitamin E or a placebo every day for four and a half years. Patients also received a drug (an ACE inhibitor) known as Altace (ramipril) or placebo daily. The trial was stopped last year when investigators felt they had enough evidence that Altace was beneficial and vitamin E was not.
"It is very unlikely that vitamin E had any clinically worthwhile beneficial effect on cardiovascular disease during four or five years of treatment," write Salim Yusuf, MD, and colleagues from the Heart Outcomes Prevention Evaluation (HOPE) study.
Heart attack, stroke, or death occurred in 16% of the nearly 4,800 high-risk patients in the vitamin E group and almost 16% of nearly 4,800 patients in the placebo group. There were no significant differences between the groups in the numbers of deaths from heart causes, heart attacks, deaths from coronary heart disease, or strokes. The total number of deaths that occurred also was similar in both groups, as was the number who required hospitalization for the crushing chest pain of angina, heart failure, interventional heart procedures, or limb amputations (approximately 38% of patients in each group had diabetes, which increases the risk for amputation).
The findings are consistent with those of several other studies that have shown no significant reduction in heart disease among people assigned to take large or small amounts of vitamin E daily.
"Up to this point there has been pretty good evidence from observational studies that long-term use of vitamin E at levels well above those found in the diet are associated with a lower risk of coronary heart disease," says Eric B. Rimm, PhD, who is associate professor of epidemiology and nutrition at the Harvard School of Public Health in Boston. Rimm tells WebMD that the HOPE trial is a well-done study with compelling results, but says the findings have numerous caveats, including the health of the participants and the length of duration of supplementation, that must be considered when translating the results to other populations and comparing them to previous studies.
Yusuf and colleagues suggest that one reason for the apparent lack of benefit of vitamin E in people with heart disease is that, unlike drugs that lower blood pressure or cholesterol, antioxidants may require a long period of use to show a benefit. However, they point out that a large study of male physicians failed to show any reduction in heart disease associated with taking another antioxidant, beta carotene, for 12 years. Similar data for vitamin E have not been reported.
Rimm says it's possible that previous studies overstated the true value of vitamin E or that preventing heart disease in people without existing disease is "a different game" than preventing a second heart attack or additional heart disease in patients with pre-existing disease. "That's a pretty strong possibility," he says. "But another strong possibility is that this study didn't go long enough to see an effect on slowing the progression of heart disease."
Rimm says, overall, the majority of trials are not in agreement and he does not believe there is enough evidence to either dismiss the benefits of vitamin E or embrace them. He says patients and their doctors must continue to decide for themselves if vitamin E is right for them, but adds that since the study did not show any harm associated with taking the vitamin pills daily, it is likely that physicians who support the vitamin E hypothesis will continue to support it and that patients will do likewise.