A new study shows dry red wines high in tannins, such as those made in southwest France and in Italy, have a greater protective effect than less tannic wines produced in other parts of the world.
Tannins are compounds extracted from the seeds, skins, and stems of grapes that give red wines their characteristic dry, full taste. As a high-quality red wine ages, its sharpness softens and the flavor becomes more complex.
The amount of tannin in a red wine like cabernet sauvignon varies, depending on the winemaking methods used.
The study's researchers say their results suggest the Old World winemaking techniques that ensure a higher amount of tannins produce wines that are healthier for the heart and may contribute to the longer longevity seen in regions known for producing such wines.
"The traditional production methods used in Sardinia and southwestern France ensure that the beneficial compounds, procyanidins [tannins], are efficiently extracted," says researcher Roger Corder of Queen Mary's William Harvey Research Institute of the University of London, in a news release.
"This may explain the strong association between consumption of traditional tannic wines with overall well-being, reflected in greater longevity," he says.
Old World Reds Healthier?
Several studies have shown that moderate drinkers of red wine have less heart disease than non-drinkers; and much of the heart-healthy effects of red wine have been attributed to the antioxidant polyphenols found in the wine. These antioxidants are thought to have beneficial effects on blood vessels and arteries.
In the study, published in Nature, researchers analyzed the polyphenol content of several types of red wine produced in various parts of the world and compared the wines' effects on blood vessel cells.
"We purified the most biologically active polyphenols, and identified them as procyanidins [condensed tannins]," says Corder.
Wines richest in these tannins had the greatest protective effect on the cells and were from regions -- Sardinia and southwest France -- that use Old World winemaking techniques.
Further research showed these areas are also associated with lower heart disease rates and higher longevity, he says.
The study found that wines made from the Tannat grape in southwest France were highest in these beneficial tannins. That grape is rarely grown elsewhere.