Scientists discover the secret behind red wine's anti-ageing properties

Red wine may be the next best thing to the fabled elixir of youth, new research suggests.

A compound in the skin of red grapes has been found to curb the effects of ageing, even when taken in tiny doses.

Scientists believe the discovery, made in mice, may explain the so-called "French paradox".

Experts have long puzzled over the fact that people in regions of France where food is soaked in saturated fat have astonishingly healthy hearts and arteries.

Plant chemicals in red wine, which often accompanies French meals, have been suggested as a possible explanation.

The new study highlights one compound, resveratrol, which is known to have anti-cancer and anti-inflammatory properties.

Experiments with mice indicated that low doses of resveratrol mimic the effects of calorie restriction to combat ageing.

Previous research has shown that reducing dietary calories by 20-30% can extend lifespan and prevent genetic changes linked to ageing in a range of animals.

Resveratrol appears to influence the same biological pathway, say the scientists.

Professor Tomas Prolla, from the University of Wisconsin-Madison in the US, senior author of the research published this week in the online journal PLoS ONE, said: "Resveratrol is active in much lower doses than previously thought and mimics a significant fraction of the profile of calorific restriction at the gene expression level."

The scientists investigated the influence of resveratrol by looking for changes in gene expression, or activity, in heart, muscle and brain tissues.

As animal's age, gene activity in different parts of the body changes as genes are switched on and off.

In the mouse heart there are at least 1,029 genes whose functions alter with age, leading to impaired function.

When mice are fed a restricted diet, 90% of this age-related change is prevented.

The study found that low doses of resveratrol blocked harmful changes in 92% of the heart genes. At the same time, declines in heart function associated with ageing were prevented.

A glass of red wine, or food supplements containing even small doses of resveratrol, were likely to represent a "robust intervention in the retardation of cardiac ageing," the scientists wrote.

Prof Prolla said: "There must be a few master biochemical pathways activated in response to caloric restriction, which in turn activate many other pathways. And resveratrol seems to activate some of these master pathways as well."

Whether or not resveratrol can extend life span will require further study, say the authors.

Resveratrol is produced naturally by plants when they are under attack by bacteria or fungi.

The compound is abundant in the skin of red grapes. Its concentration in red wine varies greatly depending on the grape variety. Normal levels are between 0.2 and 5.8 milligrams per litre, but wines produced from muscadine grapes may have more than 40 milligrams per litre.

A five ounce glass of muscadine red wine can contain as much as six milligrams of resveratrol.

Smaller amounts of resveratrol are also found in blueberries, bilberries, cranberries and peanuts.