Lately, Larry King [a paid spokesman for Welch's] has been touting Welch's Purple 100% Grape Juice on TV, implying it has the same antioxidant value as red wine. Is this true? Can you address the issue of the value of alcohol as a health food, especially wine and most particularly red wine?
-- Val Holley, Washington
I'm a huge fan of Concord grapes -- the dark purple, almost black, intensely flavored grape in season now. I've always wondered, as I enjoy these delicate treats, if they, or juice made from them, would give me or my non-wine-drinking clients the same health benefits as red wine.
Concord grapes have one of the highest antioxidant scores among fruit, surpassed only by blueberries, blackberries and cranberries. They also are high in several different types of polyphenols, antioxidants that are concentrated in many fruits, some vegetables and in wine, tea and cocoa, according to Beverly Clevidence, research leader at the United States Department of Agriculture's Diet and Human Performance Lab in Beltsville. They protect against heart disease by reducing blood clot formation. They also prevent cellular and organ damage caused by oxygen radicals, molecules that are believed to be a primary cause of many diseases including cancer and cardiovascular disease.
But if you're eating a standard American table grape, you may not be receiving many of these benefits. Half of the antioxidants are in the seed and, to please the American consumer, table grapes (and raisins) have been bred to be seedless. Much of the rest of the antioxidants are in the skin. The darker the skin, the more beneficial compounds are present, which is why green and white grapes contain a small fraction of the antioxidants that red or purple grapes contain.
Since most of the antioxidants are found in the seed and skin of the grape -- up to 80 percent, unless the flesh is darker and has more antioxidants -- a juice's or wine's antioxidant content will be higher if it includes the seeds and skin. This is why red wine contains eight to 10 times the polyphenol content as white wine. Red wine is made by mashing red or purple grapes with their skin and seeds and letting them ferment, whereas white wine is made without skin and seeds.
"Both wine's and juice's antioxidant content depends on the amount of exposure to the skin and seeds and how much extraction of the polyphenols occurs," says Andrew Waterhouse, a professor and wine chemist at University of California-Davis . "With red wine, you get maximum extraction, with the darker reds usually containing more antioxidants."
The concept of wine as a health food has been intensively researched since the "French Paradox" was first described by French researcher Serge Renaud in the early 1990s. Renaud found that while the French ate the same fatty diet as Americans, they suffered only half the rate of heart disease. He attributed that paradox to daily low-dose wine drinking. His observation made sense: The Framingham study, a long-term study established in 1948 that follows peoples' diet and health, found a link between moderate alcoholic beverage intake and reduced death rates from coronary heart disease.
Since then, other studies have confirmed a link between moderate alcoholic beverage intake and a reduction in heart disease and death rates, as compared to no-alcohol or high-alcohol intakes. But what are the most health-giving types of alcoholic beverages? Wine or spirits? And does alcohol itself -- apart from other ingredients in wine -- play a beneficial role? The answers to those questions have been debated ever since.
On the pro-alcohol side, researchers have found that pure ethanol, in any form, raises HDL, or good cholesterol, by 5 to 10 percent. But that doesn't explain the more encompassing beneficial effect of alcoholic beverages. Researchers have found that drinking wine, for instance, reduces blood clotting, hypertension-related and cardiovascular disease-related deaths and increases polyphenols in the blood, which researchers have found prevents various cardiovascular disease risk factors. But alcohol alone does not have all of these benefits. Some researchers doubt that ethanol is the most important beneficial ingredient in alcoholic beverages, and especially in red wine.
In fact, consuming high amounts of alcohol has been found to promote oxidation and inflammation, both of which are risk factors in the development of heart disease and cancer. But alcohol is often consumed with other ingredients -- cranberry, orange or tomato juice, for example. And the antioxidants in those juices may outweigh alcohol's negative effects.
In addition, researchers believe alcohol may help the body absorb the antioxidant polyphenols. "Alcohol may enhance the bioavailability of the antioxidants so that when you drink wine or other beverages or food high in antioxidants, you get more antioxidants in your blood," says John D. Folts, a professor of medicine and nutritional sciences at the University of Wisconsin Medical School.
One of the many roles the polyphenols play in the blood is they protect against the oxygen free radicals formed during digestion. After eating, the process of breaking down food increases your metabolism and this increases oxygen free radicals in your blood for several hours. Eating plenty of antioxidants with meals, including wine, fruits and vegetables, helps reduce oxidation caused by digestion and the oxidation caused by some of the less healthy components of the meal, for instance, saturated fat or potential carcinogens in the food or the environment.
So, does Concord grape juice contain the beneficial compounds as red wine? Some compounds overlap. It helps that Concord grape juice is made by pressing and pulverizing the whole grape, including the seeds and the skin, before it is strained and made into juice, according to Welch's spokesperson Geoffrey Raymond.
In preliminary animal and human clinical studies conducted by Folts and other researchers over the past 10 years, Concord grape juice and red wine produced similar cardiovascular benefits. They both raise levels of antioxidant polyphenols in the blood, reduce oxidative stress and blood clotting (which, similar to aspirin, helps prevent heart attacks). But you have to consume twice as much grape juice to produce the same effect you get from drinking red wine.
Red wine is more than alcoholic grape juice. It takes 1.5 ounces of grapes to make an ounce of wine, so it is more concentrated than juice. And the alcohol helps extract polyphenols as the wine ages. This changes the character of some of the polyphenols, and different compounds are created in ways that aren't completely understood. These differences may help explain the potent health benefits of red wine found in studies.
"Think of red wine as whole grape extract," says Waterhouse. "You're getting the antioxidants out of the juice, the skin and the seeds plus the magnifying effect of the alcohol."
Red wine contains different levels of antioxidants depending on how it's processed. Antioxidant content will also vary depending on the variety of the grape, and exposure to sunshine, which increases polyphenol content.
Understanding all the compounds and benefits is a complex issue. Experts agree that grapes, grape juice and small doses of red wine are good for you, but scientists are still unraveling the reasons why. For now, the recommendations are, if you're an alcoholic beverage drinker, women should not exceed a single five-ounce serving and men should not exceed two five-ounce servings of wine a day. Experts stress that while moderate wine intake may be beneficial for some, going above the recommendation could be dangerous to your health.
If you don't drink alcoholic beverages, eight ounces of Concord grape juice may provide similar benefits. In fact, eating a diet high in antioxidants has been proven to reduce cancer and heart disease, regardless of alcoholic beverage intake.
Katherine Tallmadge is a Washington nutritionist and author of "Diet Simple" (Lifeline Press, 2004). Send e-mails to her at firstname.lastname@example.org.