The 'topping-up' effect: differences between low- and non-alcoholic lager on blood ethanol.

The peak blood alcohol levels attained in male and female subjects after consumption of 3 pints of regular lager (4.2%) over a 30 min period was 73.5 +/- 6.9 mg% in males and 113 +/- 17 mg% in females. Peak values occurred at 60 and 90 min post-ingestion in males and females, respectively. Consumption of 3 pints of low-alcohol lager gave a maximum blood alcohol level of 13 mg% while there was no measurable blood alcohol content after three pints of non-alcohol lager. 'Topping-up' with a non-alcohol lager after 2 pints of regular lager leads to significantly lower blood alcohol levels when compared with 'topping-up' with low-alcohol lager over a comparable time in males but not in females.