MONDAY, Oct. 23, 2006 (HealthDay News) -- Drinking more than three glasses of red wine a week reduced the incidence of abnormal growths and cancers of the intestinal tract by two-thirds, a new study found.
White wine did not have the same protective effect, said study author Dr. Joseph C. Anderson, an assistant professor of medicine at the State University of New York at Stony Brook.
"I generally advise against drinking, but if you're going to drink, drink red wine," Anderson said.
The findings were expected to be presented Monday at the American College of Gastroenterology's annual meeting, in Las Vegas.
Anderson's study included 1,741 people seen in his office -- 245 red wine drinkers, 115 white wine drinkers, and 1,381 wine abstainers. Of the red wine drinkers, 176 had three or more glasses a week, as did 68 of the white wine drinkers.
The incidence of colorectal neoplasia -- cancers and polyps that can become cancerous -- was 9.9 percent in the abstainers, 8.8 percent in the three-glass-or-more white wine drinkers, and 3.4 percent in the three-glass-or more red wine drinkers, a 68 percent reduction for that group, Anderson reported.
His is the latest in a series of studies that have found red wine consumption associated with a reduced risk of various forms of cancer -- leukemia, breast and prostate among them -- in animal studies or real life. Like many of the other researchers, Anderson attributes the beneficial effect to the compound resveratrol, which is found under the skin of grapes.
Resveratrol content is higher in red than white wine because the grape skins are removed early in the fermentation process for white wines, Anderson said. The skins stay on longer when red wine is made, allowing resveratrol to enter the wine.
But that might not be the whole story, said Gopi Paliyath, a plant agriculture professor at the University of Guelph in Ontario, Canada, who has done studies that found a protective effect from red wine against breast cancer.
Resveratrol is a member of the chemical family called polyphenols, many of which are found in red wine, Paliyath said. "It may be a combined action, not only one particular component doing something," he said.
And a study done by one of his students added a potentially different element to the mix -- chemicals found in the oak barrels in which wine is made. They may leak out of the oak into the wine and act in conjunction with the polyphenols, he said.
Whatever the cause of the protective effect, Anderson said he advises people against taking up the wine habit for health reasons.
"People are better off going out exercising than hoping that a glass of wine will help them," he said. "My bias is more toward other things, like running or biking."
But, Anderson noted, his observation is that "wine drinkers are more likely to do those things."
For more on red wine and cancer prevention, visit the U.S. National Cancer Institute.