"People with a family history of cancer, especially women with a family history of breast cancer, should consider reducing their alcohol intake to below recommended limits, or even abstaining altogether," said addiction expert Dr Jürgen Rehm.
Doctors have long known that heavy drinking is a particular threat to the liver and raises
the risk of obesity and disease.
But the US findings, based on the health records of 135,000 people over 30 years, provide the most comprehensive picture yet of the impact of light drinking. The researchers found
women were at risk from just a 120ml glass of wine a day - equivalent to 1.9 units and inside the UK limit of two to three a day.
The guidelines were drawn up in 1987 and even their authors admit they were "plucked out of the air".
Sally Davies, the chief medical officer, is reassessing them and is expected to issue new guidelines later this year
The OECD report warned that as more women delay motherhood, or choose not to have children at all, they are drinking into their 30s, 40s and beyond.
And last month a separate report in the BMJ warned that drinking has become a "middle class phenomenon", with wealthy over-50s - both men and women - rapidly becoming the most problematic drinkers.
Today's study - from the Harvard School of Public Health - found that, overall, women who drank every day had a 4 per cent increased chance of being diagnosed with cancer of any type.
The picture for men was more complicated. Those who drank two 355ml bottles of beer a day (3.75 units, or a pint and a half of lager) saw an increased risk of cancer, but only if they had also smoked at some point.
Men who drank within the guidelines but had never smoked were no more likely to get cancer than a teetotaller.
But those who drank more than the advised limits did see a marked increase in risk, particularly for colorectal cancer.
The UK guidelines suggest men should drink no more than three to four units a day. Drinking is linked to breast cancer because alcohol increases levels of oestrogen, which is known to promote tumours in breast tissue.
Professor Sir Ian Gilmore, of the Alcohol Health Alliance, said: "We need mandatory health warnings on alcohol labels so that people know the facts and can make an informed choice."
Jackie Ballard, of UK Alcohol Concern, said the research showed there was no safe level of alcohol consumption.
Sarah Williams of Cancer Research UK said: "Whether you drink small amounts regularly or larger amounts less often, it doesn't make a difference to the risk of cancer - it's the amount of alcohol in total that matters. Cutting down on alcohol helps reduce the risk of cancer."
Dr Rehm is based at the Centre for Addiction and Mental Health in Toronto.
- Daily Mail
