Hopes of developing anti-ageing drugs have been given a boost by new research involving an ingredient in red wine.
Previous studies have shown that the plant compound resveratrol improves the health of mice fed a high-fat diet and increases their lifespan.
Scientists have now confirmed how this occurs. Resveratrol enhances the activity of energy-generating powerplants in cells via a gene called SIRT1, which is also linked to longevity.
Researchers are already looking at molecules that mimic the effect of resveratrol by targeting SIRT1. Such compounds could form the basis of future drugs that extend disease-free lifespan.
The effect of resveratrol on SIRT1 had been demonstrated in yeast, worms and flies before but never on higher animals.
The experiments involved a new strain of laboratory mouse whose SIRT1 gene can be switched off.
When adult mice were given low doses of resveratrol with SIRT1 disabled, no effect was seen on the cellular powerplants, called "mitochondria".
But mice with normal SIRT1 showed dramatic increases in energy after exposure to resveratrol.
"The results were surprisingly clear," said lead researcher Professor David Sinclair of Harvard Medical School in the US. "Without the mitochondria-boosting gene SIRT1, resveratrol does not work."
The findings are published today in the journal Cell Metabolism.
Resveratrol is a "dirty" molecule that can influence a number of different genes and proteins.
Other research has indicated that its metabolic benefits are derived from an effect on a different gene called AMPK.
This has raised doubts among some experts over whether SIRT1 is the right target for anti-ageing drugs.
The new studies show that even though resveratrol activates AMPK at high doses, this has no impact on mitochondria.
At low doses, resveratrol affects SIRT1 but not AMPK.
George Vlasuk, chief executive of the US biotech company Sirtris, which is trying to develop anti-ageing drugs, said: "The work.. strongly supports the basic rationale being pursued at Sirtris, which focuses on the development of small-molecule compounds that directly activate the enzymatic activity of SIRT1 as a new therapeutic approach to many diseases of ageing."
In a study at the University of Calabria, Italy, the resveratrol compound was also found to block the cancer-fuelling effects of the female hormone oestrogen, as well as inhibiting the growth of breast cancer cells that have become hormone resistant.
In a conflicting study at Harvard University it was found that women who drink just four small glasses of wine a week increase their risk of developing breast cancer by 15%, while those who drank up to four units a day were 50% more likely to develop breast cancer.
A recent study by Spanish researchers found that the alcohol in red wine and the grapes themselves may both be beneficial for the heart. The study analysed the levels of chemicals affecting inflammation and plaque on artery walls of 67 men after they drank red wine, red wine without alcohol, and gin. When the man drank the alcoholic red wine and gin, levels of chemicals that reduce inflammation increased, and when the men drank the non-alcoholic red wine, levels of chemicals that reduce plaque increased.
A study by the Centre For Addiction And Mental Health, found that while there is a positive link between alcohol use and ischaemic heart disease, it cannot be assumed for all drinkers, even for those who have a limited intake. Dr Juergen Rehm, director of social and epidemiological research at CAMH, said: "It's complicated. "We see substantial variation across studies, in particular for an average consumption of one to two drinks a day."
Research at Quebec's Universite Laval in Canada, found that chemicals found in red wine called polyphenols can block production of free radical molecules, which can damage gum tissue, it was reported by the BBC. However, dentists warn there are other risks associated with drinking wine, and people should not think it was good for their teeth.
A study at the Institute of Preventive Medicine in Copenhagen found that people who drink wine weekly or monthly are two times less likely to develop dementia. However, study author, Thomas Truelsen, MD, PhD, emphasised that "These results don't mean that people should start drinking wine or drink more wine than they usually do."
A year-long Spanish study or 4,000 volunteers found that drinking wine - especially red - can prevent people developing colds. Professor Ron Eccles, director of the Common Cold Centre at Cardiff University said the results may be due to the antioxidant properties of red wine.
Researchers from the University of Santiago de Compestela in Spain found that drinking red wine may help to ward off lung cancer. They found each glass a day reduced the risk of lung cancer by 13% compared to non-drinkers. But Cancer Research UK case doubt on the findings, warning excess drinking increases the risk of other cancers, it was reported by the BBC.