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Health Watch: Studies Find Wine Offers Benefits for Immune System

Alcohol and resveratrol can have positive effects; also, is alcohol safe during pregnancy?

Esther Mobley
Posted: January 14, 2014

Scientists from the University of Texas at Austin have uncovered evidence that the red-wine polyphenol resveratrol benefits the immune system. Several past studies have shown the chemical can have mitigating effects on weight gain and symptoms of aging, but this is the first study that suggests its potential to enhance human immunity, particularly in relation to high-fat diets.

A high-fat diet affects the thymus—the organ that prepares T-cells, which regulate the immune system—preventing the thymus from releasing as many T-cells as it otherwise might. The thymus is most active during childhood, and its early activity determines its lifelong functionality. “Basically, you set your ability to fight infectious disease in your immune system at an early age,” said Christopher Jolly, associate professor in the Department of Nutritional Sciences and a study coauthor.

Jolly and his colleagues observed two groups of mice, feeding one a high-fat diet, the other a low-fat diet. Within each group, the mice were subdivided into those receiving high and low doses of resveratrol. The high-fat subjects gained weight, but those given resveratrol showed increases in T-cells and lower thymic fat accumulation, in volumes that corresponded with the polyphenol dose they received.

In other words, “even if your diet sucks, is there something you could consume to offset those negative [immune system] effects of a high-fat diet?” Jolly asked. “Our study says, 'Yes. It’s resveratrol.'” As is typical of resveratrol research, the doses administered were much higher than conceivably could be consumed through drinking wine. Nevertheless, Jolly believes that at low doses of the polyphenol—what one might ingest from a generous daily serving of red wine, berries and peanuts—“you may start to see some beneficial effects.”

Moderate Alcohol Consumption May Fight Off Infections

Resveratrol may not be the only component of wine that boosts the immune system: New research from Oregon Health and Science University claims that pure ethanol—the alcohol in beverages—can improve one’s ability to fight off infections when consumed regularly in moderation.

The authors of the study, published in the journal Vaccine, inoculated a group of monkeys with a smallpox vaccine, assessing subjects’ responses by measuring their antibody counts. Then they let the monkeys drink: Each monkey had access to a 4 percent ethanol solution and could imbibe as he pleased. As with humans, some chose to drink heavily. A control group had access only to sugar water.

Seven months later, the researchers reinoculated the monkeys with the same vaccine. “The immune system has a type of memory, where if it sees what it’s been immunized against, it will mount an antibody response,” said Kathy Grant, a coauthor and behavioral neuroscience professor at Oregon Health & Science University. The results were clear: “The moderate drinkers produced the most antibodies against the virus,” in significantly greater volumes than those same monkeys had following their first exposure. The control group showed healthy responses, too; their antibody counts increased, though not as much as the moderate drinkers. The heavy drinkers’ immune systems responded with fewer antibodies.

“Most previous studies have shown that alcohol suppresses the immune system,” Grant told Wine Spectator. “We really didn’t expect that the moderate drinkers would have a much more robust response compared to the nondrinkers.”

Alcohol and Pregnancy Involves Many Complicating Factors

A recent large Danish study of alcohol consumption among expectant mothers surprised scientists when the findings suggested that drinking alcohol during pregnancy is associated with emotionally healthier children. Now, a doctoral candidate at the University of Copenhagen has challenged the interpretation of these findings, arguing that other factors are at play.

The Danish National Birth Cohort tracked the drinking habits of 37,315 women in early, middle and late stages of their pregnancies. The children of these women took the Strengths and Difficulties Questionnaire, a measurement of emotional and behavioral health, at age seven. The results suggest that mothers who drank a cumulative 90 units or more during pregnancy—equivalent to about two drinks per week—produced emotionally healthier offspring than their counterparts who abstained or drank very little.

“At first sight this makes no sense, since alcohol during pregnancy is not seen as beneficial to child behavior,” said doctoral candidate Janni Niclasen. “But when you look at the lifestyle of the mothers, you find an explanation. Mothers who drank 90 units or more of alcohol turn out to be the most well-educated and [have the] healthiest lifestyle overall.”

Compared with other study subjects, those drinkers were, according to Niclasen’s paper, more likely to exercise, less likely to drink cola, less likely to watch television and more likely to have a healthy pre-pregnancy BMI. They tended to be older than their nondrinking peers.

Niclasen emphasized that this is not an invitation to drink heavily while pregnant. But her research shows that when it comes to the mental health of children, prenatal alcohol exposure may matter much less than postnatal environmental factors. She wrote: "The expectedly large positive impact of the home environments of the well-educated may mask the potential small negative effects of being exposed to low doses of alcohol."

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