Healthy Living: Heady Over Grapes? (cont.)
Bagchi has labored to show that a substance within grape-seed extract, oligoproanthocyanidin, or OPC, is a powerful antioxidant. Antioxidants disarm free radicals -- molecules that can damage DNA, cells, and tissues, eventually contributing to heart disease, cancer, and other illnesses. Because of its structure, one OPC molecule can neutralize several free radicals at once, while each molecule of better-known antioxidants like vitamins C and E can handle only one at a time, Bagchi says.
Putting It to the Test
In one experiment, Bagchi and his team placed OPC, vitamin C, and vitamin E in three separate test tubes filled with free radicals similar to those found in the body. After 15 minutes, the researchers found that OPC had knocked out up to 81% of the free radicals in its test tube. By comparison, vitamin C and E neutralized up to 19% and 44%, respectively. (See the February 1997 issue of the journal Research Communications in Molecular Pathology and Pharmacology.)
While such findings are promising, they don't prove that grape-seed extract can actually prevent or cure heart disease, cancer, or any other illness, says Harry Preuss, MD, of Georgetown University, who led the cholesterol study (which was partly funded by InterHealth Nutraceuticals). "The benefits are potentially there," he says. But in order to know how a human being's health is really affected over a long period of time, "You have to do these huge, huge studies." So far, no one has been willing to pay the cost of such a study.
Patching the Pipes
Nor has anyone funded a conclusive study on the other intriguing claim made for grape-seed extract: that it reinforces collagen and elastin, the bricks and mortar of blood vessels and other supportive tissues.
If it can achieve these effects, it could benefit people suffering from a wide range of diseases. For example, it might improve capillary resistance, the ability of capillaries to hold blood. People with diabetes and high blood pressure sometimes have such low capillary resistance that their blood leaks into the surrounding tissue, causing red spots (purpura) on their skin. In one study, published in the June 8-15, 1981, issue of the French journal Semaine des Hopitaux (Hospital Week), researchers found that 13 patients who took OPC experienced much higher capillary resistance than a group of 12 people who took a placebo.
But this research, too, is preliminary -- the study didn't show whether the patients' purpura or other symptoms improved. And a good diet might be just as effective, says Rita Redberg, MD, associate clinical professor of cardiology at the University of California, San Francisco. To avoid diseases of the heart and blood vessels, Redberg says, the surest approach is eating a low-fat, high-fiber diet and getting at least 30 minutes of exercise five times a week. "If you want to do these things and also take grape-seed extract, that's fine," Redberg says.