TUESDAY, Aug. 27, 2002 (HealthDayNews) -- Studies have shown drinking wine can protect against heart disease by raising levels of so-called "good" cholesterol, but new research has now pinned down exactly how wine lovers get that extra protection.
French scientists looked at the specific components of the good cholesterol in the blood of red wine drinkers, and found men who drank red wine regularly had cholesterol that was richer in polyunsaturated phospholids and omega-3 fatty acids. Previous research has shown omega-3 fatty acids in the diet are associated with lower rates of heart disease.
"This study provides, for the first time, a detailed characterization of HDL ['good' cholesterol] composition in regular drinkers," wrote lead author Bertrand Perret, of the French medical research institute INSERM.
In the study, which appears in the August issue of Alcoholism: Clinical and Experimental Research, researchers surveyed 46 men, aged 35 to 65, about their food consumption during the previous three days. The men also completed an extensive questionnaire about their drinking habits.
More than 90 percent of the men reported drinking only red wine, not surprising since all the men in the study were from Toulouse in the south of France.
The men were put into one of three groups: teetotalers, regular drinkers (who drank less than 35 grams of alcohol daily) and heavy drinkers (who drank 35 to 60 grams a day). Wine contains about 13 percent to 15 percent alcohol. That means a regular drinker, according to this study, drinks about two glasses of wine a day.
The men were asked to fast overnight. The next morning, researchers did a chemical analysis of blood samples from the men.
Researchers found the men who were regular drinkers had higher levels of HDL cholesterol, findings that confirm an already well-documented phenomenon.
"The background is quite clear that a moderate amount of drinking -- one to two drinks a day -- has a benefit to the cardiovascular system," says Dr. David Crabb, a professor of medicine at Indiana University in Indianapolis. "This is trying to get at the basis for that finding."
Their study also found regular red wine drinkers had higher levels of omega-3 fatty acids in their cholesterol, "an effect that might be, in itself, beneficial against cardiovascular disease," Perret wrote.
Crabb says the study is interesting, but far more research needs to be done to determine if those omega-3 fatty acids in the cholesterol really protect against cardiovascular disease. The men in the study would have to be followed over time to see if they had lower rates of heart disease.
"There is a vast gulf between studies that look at dietary intake of omega-3 fatty acids and studies that look at the composition of HDL in the blood," Crabb says.
All the studies on drinking red wine come with a caveat: drinking red wine only helps if you're already at high risk of heart disease.
"This is not going to help a college student, because they're not at risk for heart disease," Crabb says. "They're more at risk of getting in a car accident because of drinking or becoming an alcoholic."
"Nobody is recommending that someone start drinking for any reason," he adds.
The American Heart Association, for example, acknowledges that research shows drinking alcohol can reduce heart disease by increasing HDL cholesterol levels. However, it cautions that regular physical activity and weight loss are other ways of raising HDL, and they don't have the downside that alcohol has.
Consuming too much alcohol can also raise the level of some fats in the blood, and lead to high blood pressure and obesity.
What To Do
The American Heart Association has information on wine and heart disease. Or read this overview of current research from the Hong Kong Academy of Medicine.
