A toast to healthy hearts: wine compounds benefit blood vessels.

Researchers have identified a class of compounds in red wine that might be responsible for much of the beverage's cardiovascular benefit. These compounds vary in concentration among wines grown in different areas and may explain some regional differences in wine drinkers' longevities.

Some researchers have suggested that the common practice of drinking red wine at meals could explain why life expectancy in France tops that in many countries where people eat lighter fare. Recent studies have suggested that people who consume a glass or two of red wine each day have healthier cardiovascular systems than those who don't imbibe.

However, these studies haven't identified components in the wine that might be responsible for these effects.

To find the active molecules, Alan Crozier of the University of Glasgow in Scotland and his colleagues worked with cells that line the blood vessels of cows. These endothelial cells--and their counterparts in people--secrete a compound called endothelin-1 that constricts blood vessels. Overly narrowed blood vessels contribute to heart attacks and strokes, Crozier explains.

He and his team gathered more than 100 red wines from wine-making regions around the world. To learn which wines might inhibit endothelin-1 production, the researchers diluted the wines and added each solution to endothelial cells growing in laboratory dishes.

Crozier's group chemically analyzed the wines and found that the best endothelin-1 inhibitors had the highest concentrations of polymeric procyanidins, which are compounds among wine's tannins.

Wines with the highest concentrations of polymeric procyanidins tend to be grown and locally consumed in areas of southwestern France and the Italian island of Sardinia, Crozier notes. Remarkably, when he and his colleagues looked at census data for cities throughout France, they found that residents of the southwest tended to have the longest life spans.

Crozier's team reports these results an the Nov. 30 Nature.

The findings are "intriguing," says Matt Kaeberlein, who studies aging at the University of Washington in Seattle. He notes that polymeric procyanidins belong to a broad family of compounds called polyphenolics. Studies have suggested that polyphenolics can ease diabetes, obesity, and some neurological diseases.

Crozier's results are "another piece of evidence that polyphenolics have a lot of interesting properties," Kaeberlein says. However, he points out that the findings fall short of showing that polymeric procyanidins are solely responsible for red wine's cardiovascular benefits. Other components in the beverage's complex chemical makeup may also play important roles.

"The only way we're going to figure out what's the ultimate benefit of compounds like this for humans is to get [the compounds] into clinical trials and see whether they have beneficial effects," Kaeberlein says.

His University of Washington colleague Peter Rabinovitch agrees, adding that health-conscious consumers shouldn't change their wine choices yet. However, since the traditional wine-making techniques still in use in southwestern France and Sardinia increase concentrations of polymeric procyanidins, he says, other vintners may soon adopt such methods.

"If I were a vintner interested in exploiting publicity given to the possible health benefits of these red wine components, I might consider evaluating my wine-making process", Rabinovitch says.