Resveratrol, a chemical found in red grapes, is more effectivein smaller doses at preventing bowel cancer in mice thanhigh doses, according to new research.

Previous research looked at high doses of purified resveratrol to study its potential to prevent cancer.It was the first study to look at the effects of a lower daily dose – equivalent to the amount of resveratrol found in one large glass of red wine – comparing it with a dose 200 times higher. Results from bowel cancer-prone mice given the smaller dose showed a 50 per cent reduction in tumour size while the high dose showed a 25 per cent reduction. Lower doses of resveratrol were twice as effective as the higher dose in stopping tumours growing, although this effect was only seen in animals fed a high-fat diet.

Samples of tumours from bowel cancer patients given different doses of resveratrol showed that even lower doses can get into cancer cells and potentially affect processes involved in tumour growth. Resveratrol is a naturally-occurring chemical found in grape skins and other plants. Laboratory studies have suggested that it may have anti-cancer properties, although results from human trials have been mixed. However, the researchers stress that the study doesn’t mean drinking red wine reduces cancer risk, as drinking alcohol increase the chances of developing the disease. Karen Brown, professor of translational cancer research at the University of Leicester, said: “For the first time, we’re seeing that less resveratrol is more. This study shows that low amounts may be better at preventing tumours than taking a high dose.

“The same might be true for other plant- derived chemicals and vitamins that are also being studied for cancer prevention. There should be more research looking at the effects of low doses. But this is early laboratory research and the next stage is for clinical trials to confirm whether resveratrol has the same effects in people at high risk of bowel cancer.” Dr Julie Sharp, Cancer Research UK’s head ofhealth information, said:“This research doesn’tmean that having a glass of red wine will reduceyour risk of cancer because you can’t separatethe resveratrol from the alcohol, and the increasein cancer risk linked to alcohol outweighs anypossible benefits of the resveratrol. “It’s a fascinating study but we need much more research to understand all the prosand cons of someone taking resveratrol to prevent bowel cancer. However, we do know that keeping a healthy weight along with a balanced diet low in red and processed meat with lots of fibre, including fruit and vegetables, can stack the odds in your favour to lower your risk of developing the disease.”