Deep Purple

photo by ADA

Original Content, The Washington Post, Wednesday, October 6, 2004; Page F01

Reader Question:

Lately Larry King [a paid spokesman for Welch’s] has been touting Welch’s Concord 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?

This is a question which has intrigued me for years. 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.

Recent research is bolstering Welch’s claims that Concord grape juice is similar to red wine in many respects, but the issue is very complex and the answer far from definitive.

To get the bottom of this mystery, let’s start at the beginning: with the grape. Concord grapes have one of the highest antioxidant scores among fruit, surpassed only by blueberries, blackberries and cranberries, according to Ronald Prior, research chemist and nutritionist at the Arkansas Children’s Nutrition Center in Little Rock. “Concord grapes contain at least fifty to sixty compounds which may play a variety of roles in the body,” says Prior.

Concord grapes are high in a class of phytochemicals (beneficial plant chemicals) called polyphenols, antioxidants which are concentrated in many fruits, some vegetables and in wine, tea and cocoa. They protect against heart disease by reducing blood clot formation. They also prevent cellular and organ damage caused by oxygen radicals, molecules which are believed to be a primary cause of many diseases including cancer and cardiovascular disease.

Certain polyphenols, such as anthocyanins, which give grapes and blueberries their purple pigment, have been found to reverse both physical and mental deficits in aging rats. Preliminary studies in humans are showing similar promising results.

Other polyphenols, called tannins, responsible for the astringent flavor in cocoa, tea, grapes, and other fruits, are powerful antioxidants.

Concord grapes also contain a tiny amount of a newly discovered polyphenol called resveratrol, primarily in the skin, which may help prevent cell proliferation and cancer. Other polyphenols found in the seed, proanthocyanidins, may also prevent cell proliferation and cardiovascular disease.

Another class of antioxidant polyphenols in grapes are called flavonols. Grapes contain the flavonols quercetin, also in apples, and kaempferol, also in broccoli, which are thought to reduce cellular proliferation and cancer.

“All of these compounds work in synergy to create health benefits,” says Beverly Clevidence, research leader of the Diet and Human Performance Laboratory at the United States Department of Agriculture’s Human Nutrition Research Center in Beltsville, MD. “They’re showing promise in our fight against cardiovascular disease, cancer, and even inflammatory diseases such as arthritis.”

But if you’re eating a standard American table grape, you may not be receiving many of these benefits. That’s because 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.

And that brings us to the juice of the grape. Since most of the antioxidants are found in the seed and skin of the grape – 80% 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 ten times the polyphenol content as white wine. Red wine is made by mashing red or purple grapes with their skin and seeds and letting it sit to ferment, whereas white wine is made skin and seedless.

“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, wine chemist at UC Davis. “With red wine, you get maximum extraction, with the darker reds usually containing more antioxidants.” Also, the more astringent the wine, the more tannins. Waterhouse says the presence of tannins is a good marker for all antioxidants: the more tannins, the more polyphenols, in general. Polyphenols are responsible for the flavor, the color and the preservation of wine.

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 heart disease rates. He attributed that “paradox” to daily low dose wine drinking. His observation made sense since the Framingham study, a long term study established in 1948 which follows peoples’ diet and health, found a link between moderate alcoholic beverage intake and reduced death from coronary heart disease.

Since then, other large epidemiological studies have confirmed a link between moderate alcoholic beverage intake and reduction in heart disease, as compared to no alcohol or high alcohol intakes. But uncovering the most health-giving types of alcoholic beverages – wine or spirits – and even if alcohol itself plays a beneficial role, have been the subject of heated debate ever since.

On the pro-alcohol side, researchers have found in clinical studies that pure ethanol, in any form, raises HDL, or good cholesterol, by five to ten percent. But that doesn’t explain the whole beneficial effect of alcoholic beverages seen in studies. Researchers have found that 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 studies comparing pure alcohol with wine show that 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, in clinical studies, 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 together with antioxidants contained in the alcoholic beverage that may outweigh its 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 Folts, professor of medicine and nutritional sciences at the University of Wisconsin Medical School. “Very few people drink straight alcohol; they mix it with juices like cranberry, orange or tomato juice, which contain antioxidants.”

Food digestion produces increased oxidative stress and oxygen radicals for several hours after the meal. Eating plenty of antioxidants with meals, including wine, fruits and vegetables, helps reduce oxidation caused by the less healthy components of the meal, for instance, saturated fat or carcinogens. This may be another reason why the French get more benefits from drinking wine: they drink it with meals.

So, does Concord grape juice contain all the benefical 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 performed by Folts and colleagues, Concord grape juice and red wine produce similar cardiovascular benefits. They both raise levels of antioxidant polyphenols in the blood, reduce oxidative stress and blood clotting. But because Concord grape juice has half the polyphenol content by volume, you have to consume twice as much grape juice to produce the same effect you get from red wine.

Red wine is more than grape juice with alcohol. Each ounce of wine contains about 1-1/2 ounces of grapes, 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 and stress, which increases polyphenol content.

Trying to understand all the compounds and benefits is a complex issue. Experts agree grapes, grape juice and small doses of 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 one 5-ounce serving and men should not exceed two 5-ounce servings of wine a day. Experts stress that while moderate wine intake may be beneficial for some, going above the recommendation can be dangerous for your health.

“Given the major problem that alcohol abuse is in many countries, it would not be good nutritional advice to tell people to start drinking wine for their health” says Dr Folts

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.

“People who eat several servings of fruits and vegetables a day have a high polyphenol intake,” says Beverly Clevidence. ”So if you don’t drink wine, just eat more fruits and vegetables!”