WEDNESDAY, Nov. 29, 2006 (HealthDay News) -- The benefits of red wine keep pouring in: British researchers now say that higher levels of procyanidins -- a compound found in red wine -- have potent protective effects on blood vessels.
But, the levels of procyanidins -- a type of flavonoid polyphenol-- vary in different types of wines, depending on where they're produced. Red wines from areas in southwest France and Sardinia, where traditional winemaking is still practiced and where people tend to live long lives, have higher levels of the compound, the researchers said.
"The endothelial cells which line our arteries are an important site of action for the vascular protective effects of polyphenols," Roger Corder, of Queen Mary's School of Medicine and Dentistry in London, said in a prepared statement. "We purified the most biologically active polyphenols and identified them as procyanidins."
The researchers then tested wines from two regions in southwest France and Sardinia and compared them with wines from other countries. The wines from France and Sardinia had surprisingly high levels of procyanidins, often five to 10 times more than wines produced elsewhere, the researchers found.
These findings suggest that although a glass or two a day can benefit the circulatory system, not all red wines provide the same amount of polyphenols.
"The traditional production methods used in Sardinia and southwestern France ensure that the beneficial compounds, procyanidins, are efficiently extracted," Corder said. "This may explain the strong association between consumption of traditional tannic wines with overall well-being, reflected in greater longevity."
The findings are published in the Nov. 30 issue of Nature.
But one expert thinks the findings need to be viewed with caution.
"People should be cautious about over-interpreting the data on longevity to imply cause-and-effect," said Matt Kaeberlein, an assistant professor of pathology at the University of Washington. "The link between procyanidins and vasodilation (widening of blood vessels) is suggestive. However, the kind of correlative population studies used for the longevity analysis are extremely difficult to control and prone to confounding factors," he added.
Some studies have reported that the increase in human longevity associated with moderate consumption of alcohol isn't specific to wine and, therefore, can't be solely the result of procyanidins and polyphenols, Kaeberlein said. "Perhaps part of the effect on human health is related to procyanidins or the combination of procyanidins with other polyphenols and ethanol. But we need controlled studies and human clinical trials to know for sure."
Another expert agrees there may not be a cause-and-effect relationship between the wines in the study and longer life.
"This is definitely another interesting correlation between substances found in red wines and potential effects on health," said Dr. Johan Auwerx, of the Institute of Genetics and Molecular and Cellular Biology in Illkirch, France.
Probably many of the compounds present in red wine have health benefits, and their combined action can contribute to the link between wine consumption and longevity, Auwerx said.
"Despite all these potential healthy effects, I would be hesitant to recommend wine as an elixir," he added. "It also has many side effects related to its alcohol content. Furthermore, it is dangerous to draw too many conclusions from correlations."
The American Heart Association can tell you more about wine and heart health.