CHICAGO Middle-aged women at risk for heart disease received little benefit from taking vitamins C, E or beta carotene, researchers said on Monday.
Though vitamin supplements provided no heart benefit, eating a diet rich in those vitamins does make for healthier heart, their study noted.
Experts believe a nutritious diet rich in these vitamins protect the body's cardiovascular system by counteracting compounds known as "free radicals." These harmful compounds build up in the body and can damage artery linings, encourage blood clots and alter the function of blood vessels.
"Single antioxidants (vitamins) may not reflect the complex vitamins and nutrients found in foods, which may explain the discrepancies between most intervention trials and studies of fruits and vegetables," wrote study author Nancy Cook of Brigham and Women's Hospital and Harvard Medical School in Boston.
"While additional research into combinations of agents, particularly for stroke, may be of interest, widespread use of these individual agents for cardiovascular protection does not appear to be warranted," she concluded.
Among the more than 8,000 women, average age 61, involved in the study only a combination of vitamins C and E conferred a slightly lower risk of stroke compared to placebos.
The participants were tracked for roughly nine years for fatal heart disease, heart attacks, strokes and heart-related surgery, the study published in the Archives of Internal Medicine said. Heart disease is the leading cause of death in the industrialized world.
"Do we expect these supplements to reverse 30 years of heart disease? Of course they won't," said Andrew Shao of the Council for Responsible Nutrition, a trade group for the industry that produces $20 billion in U.S. states annually.
"But studies show that supplementation with modest amounts of antioxidants over a long period of time, 10 years or more, (produces) modest benefits," he said. "They're subtle, as should be expected when you're talking about nutrients and not pharmaceuticals," or prescription drugs.
Importantly, the study showed taking the supplements did not harm the women, Shao said, as some recent research has suggested based on deaths from all causes.
The women consumed either 500 milligrams of ascorbic acid (vitamin C) every day, 600 international units of vitamin E every other day, or 50 milligrams of beta carotene every other day. Some consumed more than one.