Scientists warn of confusion over safe drinking guidelines around the world

International guidelines for alcohol consumption are so confusing it is enough to turn you to drink.

Scientists who studied low-risk drinking advice around the world concluded that there is a "substantial" risk of misunderstanding.

Guidelines were found to vary greatly, with measurements of the amount of alcohol in a "standard drink" ranging from 8g (Iceland, UK) to 20g (Australia).

In the most conservative countries, "low-risk" consumption meant drinking no more than 10g of alcohol per day for women and 20g for men.

But in Chile, a person can down 56g of alcohol per day and still be considered a low-risk drinker.

New UK advice introduced in January this year says men should not drink more than 14 units of alcohol per week, the same as the limit for women. The previous guidelines were 21 units for men and 14 units for women per week.

That raises another much-debated question: what constitutes a unit of alcohol? For the record, a unit translates to 10ml, or 8g, of pure alcohol - the amount of alcohol the average adult can process in an hour.

A one-unit alcoholic drink is roughly equivalent to 250ml of 4% strength beer, 76ml of 13% wine, or 25ml of 40% spirits.

The UK has now joined the list of nations, including Australia, Portugal and South Africa, that are gender-blind when it comes to drinking guidelines.

Other countries, such as the US, assign different daily or weekly limits for men and women.

Psychiatrist Professor Keith Humphreys, from Stanford University in the US, who co-led the research, said: "There's a substantial chance for misunderstanding.

"A study of the health effects of low-risk drinking in France could be misinterpreted by researchers in the United States who may use a different definition of drinking levels.

"Inconsistent guidelines are also likely to increase scepticism among the public about their accuracy. It is not possible that every country is correct; maybe they are all wrong."

He added: "If you think your country should have a different definition of a standard drink or low-risk drinking, take heart - there's probably another country that agrees with you."

The scientists, writing in the journal Addiction, surveyed the definitions of "standard drink" and "low-risk" drinking in 37 countries around the world.

They found that although the World Health Organisation (WHO) had defined a standard drink as one containing 10g of alcohol, this was not accepted by half the countries studied.

Nor was there any general agreement to follow the WHO's recommendation that both men and women should limit themselves to two standard drinks per day.

Prof Humphreys said: "More and more countries are trying to give their citizens guidelines about how much alcohol is safe to drink, and for whom. At the very least, we should know whether it's true that women should drink less than men. But even this is unclear.

"We've also learned that what constitutes a 'standard drink' in each country is far from standard, despite the WHO's recommendation.

"But in many cases these guidelines are adopted as public health policy and even printed onto alcoholic beverages without knowing whether people read them, understand them or change their behaviour as a result."