Antioxidants in red grapes get credit for keeping hearts healthy

The French get about 15 percent of their daily calories from saturated fats, an amount much higher than is recommended. But back in the 1970s, researchers started trying to figure out why the French were so healthy. Their heart disease rate is only 40 percent of the American heart disease rate. That medical mystery has been called the French paradox.

Eventually, researchers decided the secret is grapes, specifically the red grape. They contain proanthocyanidins, one of the flavonoids, which give grapes their color. And they seem to make grapes a heart-friendly fruit as well, said Dr. Cathleen London, a family practice physician on the faculty at Tufts School of Medicine, during a telephone interview.

Researchers first thought the naturally occurring compound "resveratrol" made the difference. More recent research suggests it may offer anti-cancer action but does not have benefits for the heart. Now they've homed in on phenols or tannins, compounds found in the seeds of all grapes that the body can absorb. Among them is a class of flavonoid phenols called proanthocyanidins, a more potent antioxidant than vitamin C or E. The phenolic substances are the reason for the heart-protecting properties of the grape.

They give red grapes their strong antioxidant properties. Oxidation is the process that makes us age and helps cholesterol stick to artery walls, London said. LDL cholesterol, the so-called "bad" cholesterol, isn't a problem until it oxidizes and forms plaque. Antioxidants help prevent cholesterol from becoming sticky and adhering in the first place.

Different varieties of grapes offer different levels of benefit. Rubired grapes have more proanthocyanidins than Concord grapes, for example.

The benefits occur with about 6 ounces of red grape juice, while it would take three times that much white grape juice for the same effect. And 200 milligrams of a good grape-seed extract is believed to provide the same benefits without the calories and sugar that are added to grape juice.

"You want one that is standardized, with a minimum 90 percent of polyphenols," said London, who tells her patients to look at labels to pick the right grape-seed extract.

A couple of juice companies are taking advantage of the antioxidant benefits with a "super grape juice," she said, citing Smuckers and Langers as examples. "This is the brilliance coming out of some of the studies going on in the natural food world."

She tells her patients to split a dose of grape-seed extract. To benefit, you need about 200 milligrams a day; the ideal is to take 100 twice a day, she said. It's the same with multivitamins, she added. Take it in two sittings instead of one.

The grape-seed extract should be taken with food, she added.

Grape-seed extract also has "good effects for inflammation," she said. And studies suggest that phenols can improve circulation and lessen fragility of veins and capillary walls. They also have antioxidant effects in the brain. Another study suggests they can inhibit histamine release in the blood stream, which could benefit people who have allergic reactions or even stress-induced ulcers.

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