Drinkers are being warned a large glass of wine or a pint of beer a day increases the risk of developing bowel cancer by around 10 per cent.
And drinking around two pints a day or around two large glasses of wine increases the risk by 25 per cent, the study found.
Around 35,000 new cases of bowel cancer are diagnosed in the UK each year, and almost 16,100 people die from it.
The lifetime risk for bowel cancer is one in 20 for men and one in 18 for women.
Almost 480,000 people across 10 European countries were questioned about their drinking habits as part of the ongoing European Prospective Investigation into Cancer and Nutrition (EPIC) study.
That research is funded by Cancer Research UK, the Medical Research Council and other European agencies.
The findings on bowel cancer, published online in the International Journal of Cancer, found that people who drank 15 grams of alcohol a day – equivalent to about two units – had around a 10 per cent increased risk of bowel cancer.
Those who drank more than 30 grams of alcohol – equivalent to three to four units – increased their bowel cancer risk by around 25 per cent.
In the UK, one unit equates to eight grams of pure alcohol.
Units per drink
But the number of units a drink contains depends on how strong it is and how large the measure.
All the participants in the study were followed up for a period of six years. During that period, 1,833 people developed bowel cancer.
Professor Tim Key, Cancer Research UK epidemiologist and deputy director of the cancer epidemiology unit in Oxford, said: ‘The research shows quite clearly that the more alcohol you drink the greater your risk of bowel cancer.
‘The increase in risk is not large but it is important that people understand they can reduce their risk of a number of different cancers – including bowel cancer – by cutting down on alcohol.’
Dr Lesley Walker, Cancer Research UK’s director of cancer information, said: ‘There is a lot of confusion over safe levels of drinking.
‘This partly arises over the increasing strength of some wines and beers and the fact that many pubs offer a large glass of wine that is actually equivalent to one third of a bottle.
‘It is important that people do not automatically equate one drink with one unit.
High alcohol volume
‘A large glass of wine with a high alcohol volume is likely to be the equivalent of considerably more than that.
‘Cancer Research UK recommends that women should drink less than two units a day and men less than three.’
The Government recommends that men drink no more than three to four units of alcohol per day and women drink no more than two to three.
Pregnant women and those trying to conceive are told to avoid drinking altogether.
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