Drinking several cups of coffee a day could help protect against bowel cancer, according to new research.
By Stephen Adams, Medical Correspondent
It can cut the risk of developing a tumour by between15 per cent and 25 per cent, the study of almost half a million people found.
Some previous studies have hinted that coffee could have a protective effect, but their findings have been inconclusive.
However, researchers at the US National Cancer Research Institute in Rockville, Maryland, have found evidence of a possible protective effect.
They looked at 490,000 people who agreed to have their health monitored for a decade, after answering questions about their lifestyle and diet in the mid 1990s. The research is published in the American Journal of Clinical Nutrition.
Among the sixth who said they drank four or more cups a day, the risk of being diagnosed with bowel or rectal cancer over the decade was 15 per cent lower than non-drinkers of coffee.
Among those who drank at least six cups a day, their risk was 24 per cent lower than non-drinkers.
The researchers noted that drinking decaffeinated coffee appeared to have some beneficial effect, although it was not as strong, while drinking tea had no observable effect.
They concluded: “Additional investigations of coffee intake and its components in the prevention of colorectal cancer … are warranted.”
Dr Euan Paul, executive director of the British Coffee Association, said: 'It is particularly encouraging to see that coffee consumption may lower the risk of bowel cancer given that over 40,000 men and women are diagnosed with it in the UK every year, making it the third most common cancer.”
However, pregnant women should follow NHS advice to moderate their intake of caffeine to 200mg per day from all sources, as any more than that can increase the risk of miscarriage.
Every year in Britain 40,000 people are diagnosed with bowel cancer, and it claims 16,000 lives annually.
In middle age the disease disproportionately affects men, perhaps due to lifestyle factors such as eating more red and processed meat.
If caught early the chances of long term survival are markedly better than if it is only diagnosed late, when it has spread.
In January ministers launched a nationwide bowel cancer campaign, costing £8.5 million, after advisers said the best way of increasing survival rates was to get people to recognise potential symptoms early, such as bleeding bowels.
A spokesman for Beating Bowel Cancer, a charity, said the study was "inconclusive".
He advised: "Anyone wanting to reduce their chance of bowel cancer should primarily make sure they have a healthy diet, take exercise, and stop smoking.
"Those considering increasing their coffee consumption should consult their doctor first."
Henry Scowcroft, science information manager at Cancer Research UK, said: “Many studies have looked at whether people who drink more coffee have a higher or lower risk of different kinds of cancer than those who drink a little or none at all.
"Taken together they paint a confusing picture, suggesting that it’s unlikely that coffee has a strong effect on cancer risk overall.
"This new research looked at the effects of coffee on bowel cancer, and although the results suggest a reduced risk among people who drank the most coffee, it’s only one study, and we’d need more to be able to say for sure whether this effect is ‘real’, or down to chance.”
