Sept. 11, 2000 -- At 42, Linda Walsh of Buena Park, Calif., could hardly believe that age spots were spreading up her shins and down her feet. To make matters worse, her hair was beginning to fall out, her joints were becoming stiffer by the day, and fatigue weighed every step she took.
Then she discovered grape-seed extract.
Now, four years later, Walsh's skin is free of blemishes, her hair is lustrous and full, and there's a new bounce in her stride. "I feel good and I look five years younger than before," she says. For this transformation, Walsh gives credit to an extract taken from the seeds of ordinary grapes. She's so enthusiastic that she now sells the extract and other supplements full time.
Indeed, glowing testimonials from people like Walsh have made grape-seed extract one of the most popular supplements in the United States. In 1999, Americans spent $141 million on grape-seed products, a jump of 26% over the previous year, according to The Hartman Group, a market research firm.
So do grape seeds really work? The question is far from settled, but scientists aren't ready to rule out the possibility that they might. The key ingredient in grape seeds has shown promise against disease-causing chemicals in test tubes. And a few preliminary experiments in humans have produced intriguing results.
One reason it's not easy to weigh the claims for grape-seed extract is that much of the research is done by people with a stake in selling it. Many of the studies most often cited come from the laboratory of Debasis Bagchi, PhD, a Creighton University professor of pharmaceutical and administrative sciences who also works for grape-seed product maker InterHealth Nutraceuticals.
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.
Or maybe not so fine, says Kedar Prasad, PhD, director of the Center for Vitamins and Cancer Research at the University of Colorado Health Science Center. Taking too much OPC, vitamin C, or other antioxidant, could -- theoretically at least -- add to your risk of cancer. That's because free radicals don't just damage healthy cells; they also act as a check on cancer growth. And some researchers worry that antioxidants may blunt the effects of radiation and chemotherapy used to treat cancer.
Such warnings remain hypothetical, though, and they aren't likely to sway the likes of Linda Walsh. She says that the supplement cured her son's allergies and may prevent her from suffering a heart attack like the ones that killed her mother at age 60 and her father at age 50. "People think I'm exaggerating," she says. "I'm just thankful that I found a product that helped."
Laura Lane, an associate editor at WebMD, has a master's degree in biological sciences from Stanford University. Her work has appeared in The Dallas Morning News, the Tufts University Health and Nutrition Letter, CNN Interactive, Healthy Living magazine, and Shape magazine.