Wine and Health Research You Should Know

The notion that a daily glass or two of red wine is good for the heart has been established for some time. Many studies have identified that moderate drinkers are less likely to suffer from heart disease than those who never touch it.

This report is drawn from the research of Professor Roger Corder, the other international experts who presented to the Wine & Health Symposium in Pau, France, on 30 April 2007 and subsequent press reports covering Corder's work.

Regular red wine consumption has also been proposed as an important element of the “Mediterranean diet”, which is thought to explain the greater longevity of people living in southern Europe.

Professor Roger Corder’s research, reported by New Scientist and published in the journal Nature, has now identified that one particular group of polyphenols, known as polymeric procyanidins, offer the greatest degree of protection to human blood-vessel cells.

The essense of the findings is that flavonoids in red wine called procyanidins are primarily responsible for reducing the risk of cardiovascular disease - a major factor in increased longevity. Procyanidins are antioxidants that lend pigment to grape skin and aroma to wine, and are also found in cranberries and dark chocolate. Procyanidin is believed to help keep heart tissue healthy by regulating the production of a peptide known as endothelin-1, which helps to prevent blood clots and maintain the overall health of veins and arteries. And they were effective at levels found in wines with the greatest concentrations of procyanidin.

"The endothelial cells which line our arteries are an important site of action for the vascular protective effects of polyphenols," said Roger Corder, of Queen Mary's School of Medicine and Dentistry in London. "We purified the most biologically active polyphenols and identified them as procyanidins."

Corder and his team designed their study so they wouldn't know which compound worked best until the end of the trial. The researchers cultured endothelial cells, then added small amounts of red wine to the petri dishes. The team used chromatography to isolate and measure the biological activity of each polyphenol in red wine. In hundreds of experiments, using wines from all over the world, procyanidin proved to be the best at regulating production of endothelin-1 to achieve the most favorable levels. Procyanidins suppressed overproduction by 50 percent.

Other compounds, such as resveratrol and quercetin, were found to have an "irrelevant effect," Corder said. "In order to consume enough red wine to get a beneficial amount of resveratrol, you would need concentrations that were 100- to 1,000-fold greater than what is in red wine." That claim is echoed by scientists who have conducted resveratrol studies and found that the concentration of the polyphenol found in wine is insufficient to increase longevity and boost endurance. But the procyanidins were effective at levels found in wines.

The team, led by Professor Corder and Professor Alan Crozier of the University of Glasgow, then sought to establish whether wines from any particular regions were especially rich in procyanidins. They found that procyanidin concentrations varied greatly according to winemaking style and vineyard location.

The team tested wines from two specific regions in south west France and Sardinia - linked with increased longevity - to see if they differed to wines sourced from other countries across the world.

These "traditional" wines revealed surprisingly high levels of procyanidins - with often five to 10 times more than some new world wines.

"The traditional production methods used in Sardinia and southwestern France ensure that the beneficial compounds, procyanidins, are efficiently extracted," Prof Corder said. The compound comes chiefly from grape seeds, and is extracted most efficiently by long fermentation periods with the seeds and skins for three to four weeks or more. The modern techniques used extensively in making New World wines means red wines are often fermented with seeds and skins for no more than a week, leaving fewer procyanidins in the finished wine.

Grape variety also makes a difference, and the Tannat grape used widely in south west France is particularly rich in procyanidins. Cabernet Sauvignon grapes can also produce wines with high procyanidin content, but only if wine-makers use long fermentation techniques that draw out the beneficial compounds.

These findings conclude that although a glass or two a day of the wines from south west France and Sardinia can benefit the circulatory system, not all red wines provide the same amount of polyphenols.

This may have an effect on the wider health of the local populations: both regions were selected for testing because of census data showing that they have above-average longevity, particularly for men.

One or two small 125 ml glasses of Madiran wine a day would provide between 200 and 300 milligrams of procyanidins, which studies of grape extract suggest is enough to lower blood pressure.

Professor Corder said: “There is a 19th century expression — ‘A man is only as old as his arteries’ - which can be taken to mean that those with the healthiest arteries live longer."

Wines that are rich in procyanidin are more difficult to make to high standards, they have a tannin-heavy taste, and they tend to be expensive. Smooth, sweet and very alcoholic wines that dominate the mass market are not generally high in procyanidins.

“Healthier wine is a difficult concept because too many people over-indulge on smooth, sweet, very alcoholic wines, when smaller quantities with meals is the only pattern of wine-drinking that is associated with health benefits”. "There is a tremendous variability between levels in different types of wine," said Professor Roger Corder.

"Perhaps we should be looking more at the type of wines we drink in the future if we want to try and derive some benefit from their consumption," he told reporters. A combination of both procyanidin rich foods and wines would be a healthy strategy. Procyanidins are also found in dark chocolate, some apples varieties and cranberries.

Red grapes are also high in other antioxidants called polyphenols that prevent cell damage from free radicals - unstable oxygen molecules that enter cells and damage DNA.

Corder and his team have found an explanation for the French Paradox — how a region of France renowned for its love of cheese, rich sauces and foies gras has a low rate of heart disease — when they found the local red wines were rich in the polyphenol, procyanidin.


Other research has stated that red wines also protect against dementia and delay the onset of diabetes.

Procyanidins are responsible for the health benefits of red wine - not resveratrol, which is found in the skin of red grapes and was previously believed to be the key ingredient.

Scientists have long suggested red wine protects against heart disease and had put it down to resveratrol - which increases levels of "good" cholesterol and slows production of "bad" cholesterol. Resveratrol experiments have been done on mice using high doses. Prof Corder found its levels in red wine were so low it had no effect on blood vessels at all.

Researcher Professor Roger Corder and his colleagues used cultured human endothelial cells from blood vessels to identify which component of red wine had the greatest effect on blood vessel dilatation.

Said Prof Corder: "With resveratrol you'd need to drink 1,000 litres of red wine or so a day to have any chance of affecting longevity. But procyanidins are so potent drinking just one glass a day would have an effect."