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Logo of bmjThis ArticleThe BMJ
BMJ. 2007 November 17; 335(7628): 1008.
PMCID: PMC2078648
Alcohol Confusion

What is a unit?

Rachel Seabrook, research manager

A recent BMJ editorial1 discussed the World Cancer Research Fund (WCRF) report on cancer2 and commented on the report's recommendation that men should drink no more than two units of alcohol a day and women no more than one unit a day. These recommendations are much lower than current government advice in Britain.2 This highlights a widespread confusion regarding units of alcohol and “standard” drinks—WCRF “drinks” contain 10-15 g of ethanol and British units contain 8 g.

Although a unit is often taken as one drink (half a pint of beer or one glass of wine), this is not the case. One pint of beer (4.2%) contains 2.4 units and a 175 ml glass of wine (12%) contains 2.1 units. The Department of Health leaflet, How Much is Too Much?, promises information on the number of units in alcoholic drinks. It advises using smaller glasses, stating that a 125 ml glass of wine contains one unit.3 This would be true if the alcohol content was 8%, but at a more typical 12% it contains 1.5 units.

Furthermore, the standard drink varies across the world. The WCRF report is an international publication, which may explain the wide range of ethanol contents per drink (10-15 g) in the recommendation.

In 1991, Miller et al issued “a plea for consistency” regarding alcohol content.4 Given the ambiguity present in the WCRF report, and the confusion evident even in a BMJ editorial, it is surely time to heed that plea.


Competing interests: None declared.


1. Key T. Diet and the risk of cancer. BMJ 2007;335:897. [PMC free article] [PubMed]
2. World Cancer Research Fund/American Institute for Cancer Research. Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington DC: AICR, 2007
3. Department of Health. How much is too much? 2006. London: DoH.
4. Miller WR, Heather N, Hall W. Calculating standard drink units: international comparisons. Br J Addiction 1991;86:43-7.

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