In Hong Kong, the Department of Health’s recommended daily limit is two standard drinks for men and one standard drink for women. The city defines a “standard drink” as one containing 10 grams of alcohol.

Wide variation in definitions of “standard drink” and governmental guidelines on “low-risk drinking” have been found in a study by researchers at Stanford University School of Medicine published in the journal Addiction. It is confusing, the experts say, both for people trying to drink responsibly and for researchers wishing to study global patterns of alcohol use and addiction.

“There’s a substantial chance for misunderstanding,” says the study’s senior author, Keith Humphreys, a professor of psychiatry and behavioural sciences. “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.”

Humphreys and colleague Dr Agnes Kalinowski, a psychiatric medicine resident and the study’s lead author, surveyed the definitions of “standard drink” and low-risk drinking in 75 countries around the world.

Only 37 countries had alcohol guidelines, and the guidelines and “standard drink” definitions were surprisingly inconsistent. Most did not use the World Health Organisation guidelines, which define a “standard drink” as one containing 10g of alcohol and advise both men and women not to exceed two standard drinks per day.

The size of a standard drink was found to vary by 250 per cent, from a low of 8 grams of alcohol in Iceland and Britain, to 14 grams in the US, to a high of 20 grams in Austria.

Want to drink more? Australians are told they should drink no more than 20 grams each day; in the US, women are allotted 42 grams per day but no more than 98 grams per week, and men 56 grams per day and up to 196 grams per week. The upper weekly limit for men in Poland is substantially higher, at 280 grams.

Got a reason to celebrate? In Australia, Canada, Denmark, Fiji, France, Mexico, New Zealand, Poland, and Britain, you are allowed to drink more on special occasions.

Tired of the old double standard? In Australia, Grenada, Portugal, South Africa and now Britain, low-risk drinking guidelines are the same for women and men.

The variability seen by the researchers reflects the need for more study about responsible alcohol consumption and also the differences in cultural attitudes among countries, according to Humphreys.

“More and more countries are trying to give their citizens guidelines about how much alcohol is safe to drink, and for whom,” says Humphreys. “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.”

Common alcoholic drinks and their alcohol content measured in “standard drink units” in Hong Kong

Note: In Hong Kong, one standard drink is approximately equivalent to 10 grams of pure alcohol.

These values are approximate and for reference only and may vary depending on brand chosen.

Source: Department of Health