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Even light and moderate drinking - up to one drink a day for women and two drinks a day for men - could increase the risk of cancer, say researchers.

The work in the British Medical Journal looked at two large US studies involving more than 100,000 adults.

The clearest link was for breast cancer.

Experts say the findings reinforce the health message that people should limit how much they drink and have some alcohol-free days.

There is no guaranteed safe level of drinking, but if you drink within the recommended daily limits, the risks of harming your health are low, they say.

The risks

Alcohol is linked to an increased risk of mouth, throat, gullet, bowel, liver and breast cancer

Smoking and drinking together further increases cancer risk

All types of alcohol increase cancer risk

The more you drink, the higher the risk

Cutting down on alcohol can reduce cancer risk

Source: Alcohol facts and evidence - Cancer Research UK

The NHS recommends that men should not regularly drink more than three to four units (two cans of 4.5% lager) a day and women two to three units (two small glasses of 12% wine) a day - although these drinking guidelines are currently under review and so could change.

In the American studies, light to moderate drinking was defined as up to 15g alcohol (a small glass of wine) per day for women and up to 30g alcohol (two 355ml bottles of beer) per day for men.

For women, the researchers observed, the risk of alcohol-related cancers - mainly breast cancer - increased even after one alcoholic drink a day.

No significant link was found in men who had never smoked, but among men who were current or ex-smokers, light or moderate drinking appeared to increase the risk of certain cancers.

Know your limits

In an accompanying editorial, Dr Jurgen Rehm at the Centre for Addiction and Mental Health in Toronto, said people with a family history of cancer "should consider reducing their intake to below recommended limits or even abstaining altogether, given the now well-established link between moderate drinking and alcohol-related cancers".

UK experts stressed that the overall risk for an individual person who drinks a light or moderate amount of alcohol is likely to be small.

Image copyright LEONELLO CALVETTI/SCIENCE PHOTO LIBRARY Image caption Take into account the size of the glass and the strength of the drink when you are calculating how many units of alcohol you have had

Sarah Williams, Cancer Research UK's health information manager, said: "Cutting down on alcohol helps reduce the risk of cancer, so try having more alcohol-free days each week or swapping every other drink for something soft on a night out."

Dr Richard Roope, of the Royal College of GPs, said: "GPs do not want to be killjoys - but we want our patients to live long and healthy lives, and lifestyle habits, such as smoking and drinking alcohol, are very real risk factors in developing cancer that can't be ignored."

A Department of Health spokesman said: "Whilst we have seen a fall in the number of people drinking heavily on a regular basis, drinking even small amounts of alcohol regularly can increase the risks of some health conditions.

"We want advice for the public about alcohol to be as clear and relevant as possible, which is why the Chief Medical Officer has brought together a group of experts to review current guidelines."

Prof Sir Ian Gilmore, chairman of the Alcohol Health Alliance UK, called for mandatory health warnings on alcohol labels to help consumers make an informed choice.

"We all have a right to know what we are putting into our bodies and, at the minute, consumers are being denied this right."