While some studies suggest moderate alcohol consumption can reduce heart disease, the same amount of alcohol may damage a person's DNA, increasing their risk of cancer by 20 percent, said Dr. Rachel Thompson, a spokeswoman for the cancer research fund.

"When you consider how many cases of these types of cancer are diagnosed in the (United Kingdom) every year, it is clear that drinking even relatively small amounts of alcohol can make a significant difference," Thompson said.

Each year in Britain an estimated 36,500 people are diagnosed with bowel cancer and another 3,000 with liver cancer, said Britain's National Audit Office, which estimates 10 million Britons now drink to "hazardous" levels.