Vitamins may greatly reduce the risk of heart attacks and the need for further surgery in people with coronary artery disease, according to new research released Wednesday.
Two studies, published in today's New England Journal of Medicine, show substantial benefits from vitamins.
In one, studying people who had undergone angioplasty to unblock coronary arteries, taking supplements of B vitamins helped keep the blood vessels from becoming blocked again.
In the other study, combining niacin, one of the B vitamins, with a cholesterol-lowering drug greatly lowered the rate of heart attacks for patients with coronary artery disease. The effect of the combination was considerably greater than that observed for cholesterol-lowering drugs alone.
However, the study also showed that large doses of antioxidant vitamins--once thought to protect the heart--offered no benefit. The anti-oxidants actually interfered with the gains of the niacin therapy when the two were taken in combination, suggesting that at least some heart patients should consult their doctors before taking extra amounts of antioxidants such as vitamins C and E.
"Both studies are good news," said Dr. Michele Hamilton, associate professor of cardiology at UCLA and co-director of the UCLA heart failure program. "They're showing we're homing in on the most effective ways to try to reduce the risk of heart attacks and prevent the progression of coronary artery disease."
The studies suggest that doctors should consider vitamin therapies with at least some of their heart patients, Hamilton and other experts said. But they also stressed that the studies were small and that patients should beware of taking supplements without consulting their doctors. Niacin, for instance, can sometimes cause liver complications.
In one of the two studies, a team led by cardiologist Dr. Greg Brown of the University of Washington at Seattle treated 160 patients with blockages in the coronary arteries.
One group received simvastatin, one of the statin family of drugs that reduces low-density lipoproteins, the so-called bad cholesterol. They also received niacin supplements, which have been shown to raise levels of high-density lipoproteins--good cholesterol.
A second group received large doses of antioxidants (vitamins E, C, beta-carotene and selenium); a third received the statin and niacin plus antioxidants; a fourth got a placebo.
At the end of three years, the coronary arteries of the people receiving niacin and the statin were less blocked than those of the other groups.
Most importantly, the risk of heart attack and other complications was 60%-90% lower in the statin-niacin group compared with those receiving either placebo or antioxidants. The protective effect was blunted when antioxidants were added to the mix.
The other study, conducted by UC San Diego cardiologist Dr. Guido Schnyder and colleagues, sought to address a big problem in cardiology: 20% to 40% of patients receiving balloon angioplasty to unblock clogged coronary arteries experience a re-narrowing of the artery. Many need repeat surgeries.
In the study, 205 Swiss patients who had undergone balloon angioplasties were treated for six months with either a cocktail of B vitamins (folate, vitamin B-6 and vitamin B-12) or a placebo.
At the end of the trial, those who had gotten the vitamins had about half the rate of clinically significant artery re-narrowing and a similarly reduced need for new surgery.
The likely reason: reduced levels of a blood amino acid, homocysteine, which has been implicated as a risk for heart disease.
The link between blood homocysteine and heart disease risk has been implied for some time, said Dr. Fredric Kraemer, professor of medicine at Stanford University and president of the American Heart Assn.'s western states affiliate.
But "this is the first study of significant size showing that this type of therapy may well be beneficial," he said. It now needs to be demonstrated in a broader group of people, he added.