GAINESVILLE---Unlike many other alcoholic beverages, red wine does not suppress the immune system, according to preliminary studies at the University of Florida. While red wine has been reported to aid in the prevention of coronary heart disease and some cancers, no one has studied whether its alcohol content might offset any benefits, said food science and human nutrition researcher Susan Percival.
So Percival, who specializes in nutrition and immunity, conducted a study to find out if red wine affects the immune system. Her research shows that the circulating white blood cells that fight infection are not helped -- or hurt -- by red wine.
"There's been a lot of publicity lately on the health benefits of red wine, but we also know that alcohol suppresses the immune system," said Percival, a researcher in UF's Institute of Food and Agricultural Sciences. "So we wanted to find out whether red wine had a suppressive effect on immunity."
In the eight-week study, laboratory mice were divided into four groups of drinkers: teetotalers, who drank only water; wine drinkers, with one group getting cabernet sauvignon and the other getting muscadine wine; and ethanol drinkers, who received alcohol in concentrations equivalent to that in the wine.
The study was designed to replicate moderate alcohol consumption for people, so the mice were given the equivalent of two or three glasses, or servings, of wine or alcohol per day.
After the mice had established a drinking habit, Percival made the mice mildly ill to see how their immune systems would respond under the influence of alcohol.
The mice who were drinking ethanol experienced a suppressed immune response, while the mice who drank wine maintained normal immunity.
"We found that the animals that consumed straight ethanol had lower levels of white blood cells than any other group," Percival said. "However, the same amount of alcohol, consumed as red wine, resulted in no suppression of the immune response.
"What this suggests," Percival said, "is that there's something in red wine that prevents suppression of the immune system. So it's OK to drink a glass of red wine. You can get the benefits without any apparent harm on immunity."
Percival said there are many different compounds in red wine and in grapes that could be contributing to the results, but she has not yet pinpointed which specific compound aids in maintaining normal immunity. The rich pigment in red wine is due to antioxidants and blood tests showed that mice who drank wine had two times more antioxidant capacity than the animals who drank ethanol or water.
Percival used cabernet sauvignon and muscadine wine to see if the variety of wine affected the immune response. The cabernet grapes came from California and the muscadine grapes from a local vineyard in North Central Florida. The wines were made at the food science and human nutrition department by researcher Charlie Sims.
Percival said she found the comparison of muscadine and cabernet inconclusive. Tests of enzymes in the liver, which detoxifies alcohol for the body, showed some differences between how the liver processed the two wines. Percival said she hopes to do further studies to determine whether muscadine might have greater protective effects because of its greater concentration of antioxidants.
"I was surprised to find no immune system suppression from the red wine, and we still don't know what it is that prevented the suppression," Percival said. "So we'd like to take this further and eventually look at this process in people."
Materials provided by Institute Of Food And Agricultural Sciences, University Of Florida. Note: Content may be edited for style and length.
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