A substance found in red wine may protect the body against age-related diseases by stimulating an evolutionary defence mechanism that guards human cells against genetic damage, say scientists.
Resveratrol, an organic compound found in grapes, nuts and a variety of other edible plants, has already been linked with extending the healthy life of laboratory animals as well as decreasing the incidence of heart disease and other illnesses in humans.
As red wine is particularly rich in resveratrol, some researchers have suggested it could explain the "French paradox" of a relatively high-fat diet but relatively low incidence of coronary heart disease within the wine-drinking population of France.
Nevertheless, scientists have disputed the supposed effects of resveratrol. The study found that resveratrol mimics another molecule found naturally in the body that is involved in activating an ancient chemical pathway to limit stress and damage to the DNA of cells - which would otherwise result in ageing and disease.
"This stress response represents a layer of biology that has been largely overlooked, and resveratrol turns out to activate it at much lower concentrations than those used in prior studies," said Professor Paul Schimmel of the Scripps Research Institute in La Jolla, California, who led the study published in the journal Nature.
The researchers found that resveratrol mimics a naturally occurring amino acid called tyrosine which normally binds to one of a family of enzymes. One of these enzymes, known as TyrRS, becomes activated when resveratrol binds to it, helping to protect the DNA of the chromosomes against genetic damage.
Relatively small levels of resveratrol caused the response, said Matthew Sajish, co-author of the Scripps study.
"Based on these results, it is conceivable that moderate consumption of a couple of glasses of red wine would give a person enough resveratrol to evoke a protective effect," Dr Sajish said.