Health Watch: A Glass Of Wine Offers More Than Resveratrol

Can wine help you live longer? That's the question taken up by two scientific studies published this month, with very different results.

Researchers from Johns Hopkins found that among 783 subjects, resveratrol, wine's most famous polyphenol, was not associated with longevity. A different investigation, however, shows a strong link between a diet rich in polyphenols and increased lifespan.

For the latter paper, researchers at several Spanish institutions and Harvard University consulted data from the PREDIMED trial, best known as the study that confirmed the benefits of the Mediterranean diet. PREDIMED (Prevención con Dieta Mediterránea) tracked the diets of 7,447 Spaniards, ages 55 to 80, over several years. It found that those who ate diets rich in olive oil, nuts and red wine had better cardiovascular health than those who consumed a low-fat diet.

In this new study, "we had the ability to go back and say, 'Hey, what else was in their diet?'" said Dr. Eric Rimm, associate professor of epidemiology and nutrition at Harvard School of Public Health and an author of the paper.

Rimm and his associates conducted a re-analysis of the PREDIMED data to see what subjects' polyphenol consumption looked like, and whether that might be connected to longevity. Many of the foods in the Mediterranean diet are high in polyphenols. They hypothesized that "if polyphenol intake does protect against the development of chronic diseases” such as cardiovascular disease and type 2 diabetes, “a greater combination of polyphenols would contribute to lower the risk of all-cause mortality and provide a greater life expectancy."

Sure enough, the group that consumed the highest levels of polyphenols was 37 percent less likely to die during the nearly five years of follow-up examinations than the group that consumed the lowest levels. Rimm was able to stratify the data even further, and found that two groups of polyphenols, stilbenes and lignins, were associated in particular with a reduced mortality risk. (Resveratrol is a stilbene.)

So do Rimm's results contradict those from the Johns Hopkins researchers? Not necessarily. "There's enough evidence now that resveratrol or resveratrol-like compounds by themselves probably are not associated with longevity," Rimm told Wine Spectator.

But the total effects of a diet rich in all kinds of polyphenols, derived from many different food sources—that’s a different story. "Total polyphenol intake: We think there's something there," he said. "I'm not a big fan of finding one compound, extracting it and putting it in high doses in a pill. Food may enhance the benefits of a stilbene or a lignin."

The physical mechanism by which polyphenols exert their life-expanding power is still unclear. For now, rather than isolating single polyphenols in animal trials, Rimm is more interested in observing the long-term effects of total polyphenol intake in the diet of large populations.

"What would happen if we did the same thing [as PREDIMED] in an American population, an Italian population, in the Netherlands, in the U.K.?” Rimm asked. “If we can see that [the benefits of polyphenols are] consistent in these other populations, that will lend a lot of credence to our results here."

Brush, floss and drink a glass of red wine

Might red wine’s benefits for your teeth outweigh its potential for harm? Previous research has suggested that wine, largely because of its acidity, can erode tooth enamel. But a new paper in the Journal of Agricultural and Food Chemistry claims that red wine has antimicrobial properties that may prevent periodontal disease and the loss of teeth.

Teeth are especially susceptible to bacteria—once a microorganism latches onto a tooth, it's liable to stay there, producing high levels of acid, which over time demineralize teeth and can lead to disease. Scientists have been looking for an effective antimicrobial application for the mouth with as few side effects as possible. (Some existing remedies can dull one’s sense of taste.)

For this study, researchers from universities in Madrid and Zurich used a biofilm model—a collection of microorganisms that resemble human dental plaque, to which they added five species of bacteria that could cause mouth disease. Since polyphenols have been known to combat bacteria, the scientists applied red wine, de-alcoholized red wine, red wine with grape-seed extract, water and a 12 percent ethanol solution to the biofilm.

Their results revealed red wine with added grape-seed extract as the most effective antibacterial agent, fighting three of the five bacterial strains. The red wine, both dealcoholized and not, proved effective against two of the strains.

Binge drinking: Still a bad idea

A new study on the effects of binge drinking examines what precisely happens to the body after four or more drinks in rapid succession. "Our observations suggest that an alcohol binge is more dangerous than previously thought,” said Dr. Gyongyi Szabo, professor of medicine at the University of Massachusetts Medical School and a study author.

Szabo and her colleagues recruited 25 subjects—11 men and 14 women between the ages of 21 and 56—who were healthy and had no history of alcohol abuse. The subjects received cocktails made of vodka and orange-strawberry juice, proportions adjusted by body weight so that all subjects' blood alcohol content would reach .08 grams per deciliter within an hour. Blood samples were taken every 30 minutes for the first four hours, then again 24 hours after consumption.

The single episode of binge drinking led to subjects showing increased levels of endotoxin—consistently high levels of which can lead to liver disease—and bacterial DNA, an indication that bacteria has infiltrated the gut. Because endotoxins and bacterial DNA incite the immune system to action, they could lead to problems such as inflammation. "We found that a single alcohol binge can elicit an immune response,” said Szabo, “potentially impacting the health of an otherwise healthy individual.”