A natural substance found in red wine can extend life and counter the negative effects of an unhealthy high-fat diet, a study has found. The findings may go some way to explain the "French paradox" of a national diet rich in animal fats apparently not resulting in excessive deaths from heart disease.
The study was carried out on mice fed on a diet so high in saturated fats that it was equivalent to eating a cream cake with every meal. Mice on the fatty diet became obese, suffered health disorders such as liver and heart disease and died significantly earlier than mice on normal diets.
But when a second group of mice on the high-fat diet were given resveratrol, a plant extract found in grapes, their health and longevity were almost indistinguishable from normal mice, although they still became obese.
Resveratrol has already been shown to extend the lifespan of yeast, worms, flies and fish but this is the first study to demonstrate the same effects on warm-blooded mammals. "After six months, resveratrol essentially prevented most of the negative effects of the high-calorie diet in mice," said Rafael de Cabo of the US National Institute on Ageing.
The study, published in the journal Nature, demonstrated that resveratrol changed the metabolism of the mice in such a way that they were more protected against the side-effects of an unhealthy diet, said Professor David Sinclair of Harvard Medical School in Boston.
Resveratrol is produced by a range of plants in response to environmental stress and it appears to work by activating a key gene in mammals called SIRT1 which produces an enzyme link-ed to extending lifespan.
Professor Sinclair said: "[It] may mean we can stave off in humans age-related diseases such as type-2 diabetes, heart disease, and cancer, but only time and more research will tell."
Fat, middle-aged mice in the study were far more likely to die prematurely compared to normal mice. Yet when given resveratrol the risk of death in the same group fell by 31 per cent - putting then on a par with mice on a healthy diet.
"We won't have final lifespan numbers until all of the mice pass away," said Professor Sinclair, "... but there is no question we are seeing increased longevity."
Other tests showed that the mice given resveratrol outperformed their fat cousins in terms of agility and co-ordination. "The mice on resveratrol have not been just living longer, they are also living more active, better lives.," Professor Sinclair said.
Matt Kaeberlein and Peter Rabinovich of the University of Washington in Seattle warned people not rush out and buy resveratrol. "Many people will wonder whether they should start supplementing their diets with resveratrol," they say in a Nature editorial. "Our advice is to exercise caution. The safety of resveratrol at the high doses in humans comparable to those used [in the study] is unknown, especially over the course of years or even decades."
"For now we counsel patience. Just sit back and relax with a glass of red wine - which, alas, has only 0.3 per cent of the relative resveratrol dose given to the gluttonous mice."
The effects on mice
* Mouse fed on a standard diet grew to normal size and lived an average lifespan. Tests showed no signs of damage to organs or ill health
* Mouse fed on high-fat diet became overweight and suffered observable damage to liver, heart and malfunctions in metabolic pathways. Died prematurely
* Mouse fed on high-fat diet with resveratrol also became obese but had a normal lifespan. It was more active and vital organs were undamaged by its dietReuse content