Antioxidants, Drugs Battle It Out Against Heart Disease
The cholesterol-lowering drugs that were used were Zocor and niacin. Zocor belongs to a class of drugs called "statins," which also include Lipitor and Pravachol.
The researchers found that antioxidants had no effect on cholesterol levels when taken alone. However, Zocor and niacin together improved cholesterol significantly. LDL fell 42% while HDL rose 26%.
The results of the study are published in the Nov. 29 issue of The New England Journal of Medicine.
The researchers then looked at each person's blood vessels in the heart to see how much blockage there was -- keeping in mind that each participant in the study was already known to have heart disease.
Antioxidants were no better than placebo at stopping the progression of heart disease. However, the cholesterol-lowering drugs were able to actually lessen the blockage.
And in a surprising, yet concerning, finding, the researchers found that when antioxidants were added to cholesterol-lowering drugs, not only did the blockage not improve, but it actually continued to worsen.
The next step was to see if the different treatments actually led to different results -- and they did.
The researchers looked at the number of people who, over the three-year study, suffered a heart attack, stroke, or required another procedure to open blocked arteries.
While about 21%-24% of those taking antioxidants or placebo experienced further problems, just 3% of the people taking Zocor and niacin suffered the same fate.
And again, when antioxidants were added to the drugs, things didn't go as well -- with 14% of them having a heart attack or stroke.
The researchers were able to pinpoint one possible reason why antioxidants might actually be harmful in the prevention of heart disease. The antioxidants lowered the amount of one type of HDL cholesterol. And while the drugs improved HDL cholesterol when used alone, when the antioxidants were added, the benefit was less.
The researchers say that unless more compelling evidence comes along in support of antioxidants, they see little reason to use them -- especially since they might actually make things worse.
But Jane E. Freeman, MD, points out that the findings, although intriguing, might not be relevant to people who don't already have heart disease. In other words, the possibility still exists that antioxidants might be helpful in preventing heart disease in healthy people. Freeman, who wrote an editorial accompanying the study, is from Boston University School of Medicine.