Antioxidants Don't Protect the Heart
Some Antioxidant Vitamin Supplements May Harm Heart
June 12, 2003 -- Antioxidant vitamins not only may not help the heart, they may actually hurt it. In a new study, vitamin E supplements did not help prevent heart disease, and too much vitamin A increased the risk of dying from a heart attack or stroke.
Cleveland Clinic researchers compiled data from seven vitamin E trials and eight trials in which participants took supplemental beta carotene, a source of vitamin A. More than 15,000 people took part in the antioxidant vitamin studies, and follow-up ranged from one to 12 years.
Vitamin E showed no benefit in preventing deaths from heart disease, stroke, or any other cause.
But when it came to beta carotene, the results were even more discouraging. Compared with people who did not take the antioxidant vitamin, people who took beta carotene had a small but significant increase in deaths from heart disease and stroke as well as other causes of death. The findings are published in the June 14 issue of The Lancet.
Dispels Antioxidant Claims
Lead researcher Marc S. Penn, MD, says he conducted the study because the public and even many healthcare providers still believe antioxidant vitamins protect against heart disease.
"For people at risk for [heart attacks and strokes], relying on antioxidant vitamins is not going to help," he says. "What will help is having your cholesterol checked, having your levels of arterial inflammation checked, and treatments that we know benefit patients, such as [cholesterol-lowering] statin therapy and aspirin therapy."
Penn says taking supplemental beta carotene or vitamin A should be discouraged. That is especially true for people who are at increased risk for heart disease. Recent studies also suggest that too much vitamin A in the diet weakens bones and increases the risk of fractures.
But do the findings mean it is a bad idea to take multivitamins that contain vitamin A or beta carotene? Penn says no, because most multivitamins do not exceed the government's recommended daily allowance for any one vitamin. Most study participants took dosages of the antioxidant vitamins that far exceeded these recommendations.
Healthy Lifestyle the Best Defense
Cardiovascular nutrition researcher Alice Lichtenstein, D.Sc, says the Cleveland Clinic finding should come as no surprise to anyone who has been following the latest findings on antioxidant vitamin supplements, but they may help focus the public's attention back where it belongs.
"From a nutritional standpoint, there are no easy answers for preventing heart disease," she tells WebMD. "The idea that you could open a vitamin E capsule and dribble it all over a hot-fudge sundae, and that would be protective, was never very realistic."
While there is early evidence that supplements of the vitamin folic acid may reduce inflammation and lower heart disease risk, Lichtenstein says it is way too early to suggest that people take more than the recommended daily amount to protect their hearts.
The evidence is even stronger that the omega-3 fatty acids found in fish oil protect against heart disease. So strong, in fact, that the American Heart Association now recommends eating at least two servings of fish each week.
But Lichtenstein, who directs the Cardiovascular Nutrition Laboratory at Tufts University, says it is not likely that any single food or nutritional supplement -- including antioxidant vitamins -- will ever be found to protect the heart as well as an overall healthy diet and lifestyle.
"The best advice we can give with respect to diet and lifestyle is to maintain a healthy body weight, and to consume a diet high in fruits and vegetables, whole grains, fish, and non-fat and low-fat dairy products."