Study: Vitamin E and other antioxidants may blunt benefits of cholesterol drugs
Wednesday, November 28th 2001, 12:00 am
By: News On 6
BOSTON (AP) _ Loading up on vitamin E and other antioxidants is probably worthless for heart patients and may even interfere with widely used cholesterol-lowering drugs, a study found.
Antioxidant nutrients, especially vitamin E, were widely recommended a few years ago as a promising way of keeping the heart healthy. However, several recent large studies that tested the idea failed to show any benefit, and now a new one raises the possibility that the pills might even be harmful for some.
The latest study is relatively small and leaves some questions unanswered. Nevertheless, it is one more bit of discouraging news for what once seemed like a cheap, simple way of warding off heart trouble.
The study suggests that antioxidants may blunt the benefits of statins and niacin, which are used to lower LDL, the bad form of cholesterol, and raise HDL, the good kind of cholesterol that keeps the arteries flowing smoothly.
Antioxidants are ``not proven to be of any value. In fact, they interfere,'' said Dr. B. Greg Brown of the University of Washington.
Statins _ sold under such brand names as Zocor, Pravachol, Lipitor, Mevacor and Lescol _ are taken by millions of Americans and are recommended for millions more.
Antioxidants theoretically protect the heart's arteries by blocking the damaging effects of oxygen. The approach works in animals, and studies show that healthy people who eat vitamin-rich food as well as take some antioxidant supplements seem to have less heart disease.
However, only one major study set up to rigorously test the theory in people who already have heart disease has shown a benefit. Several others _ including a British study of 20,000 patients released earlier this month _ have found no effect at all.
Brown's research was conducted on 160 people with heart disease whose LDL levels were normal but HDL was low _ under 35 in men and 40 in women. This is a common situation, affecting about 40 percent of people with heart disease.
Doctors tested the effects of a combination of Zocor and niacin, which is vitamin B3 but not an antioxidant. Some also got large doses of four antioxidants _ vitamins E and C, beta carotene and the trace element selenium.
The latest results of the study, funded by the National Institutes of Health, were published in Thursday's New England Journal of Medicine. The report adds detail to an earlier version carried in the August issue of Atherosclerosis, Thrombosis and Vascular Biology.
After three years, just 3 percent of the people getting Zocor plus niacin suffered new heart attacks or strokes, had died, or needed bypass surgery or angioplasty. In comparison, 14 percent of those who added antioxidants to their drugs had these bad outcomes.
Buildups in the patients' arteries actually shrank slightly in the patients on Zocor and niacin, while they increased minimally in those who also took antioxidants.
Brown attributed the poorer outcome in those on antioxidants to a smaller rise in their HDL-2, a fraction of the HDL cholesterol that appears to be especially protective.
Dr. Eric Rimm of the Harvard School of Public Health, who found an apparent benefit of vitamin E on healthy people in a study eight years ago, noted the latest study's small size and the fact that it didn't sort out the effects of various antioxidants, which may differ.
``I don't think it is so compelling that people should be scared to take vitamin E,'' he said, although ``the weight of the evidence suggests there probably is not a benefit in people with existing coronary disease.''
Dr. Norman Krinsky of Tufts University, who headed an Institute of Medicine panel on antioxidants, said the study ``raises a real question'' about the possible interference of the nutrients with cholesterol drugs. But he said ``a blanket condemnation of antioxidants for prevention may be premature.''
A second study in the journal, conducted by Dr. Guido Schnyder of the University of California at San Diego, found that another vitamin cocktail is good for people undergoing balloon angioplasty. The combination of folic acid, vitamin B12 and pyridoxine reduced the risk that arteries will clog up again from 22 percent to 11 percent.
The treatment apparently works by lowering levels of homocysteine, an amino acid long implicated in heart attacks.