Consuming wine at home from 50 cl bottles, compared with 75 cl bottles, may reduce both the amount of alcohol consumed and the rate of consumption, a study from the UK has found.¹

The investigators, from the University of Cambridge, undertook a randomised controlled crossover trial, comparing consumption of wine in 75 cl and 50 cl bottles, with a ‘usual behaviour’ period before the crossover. 

A total of 186 UK households that reported consuming between two and eight 75 cl bottles of wine a week were recruited to the study. Eligible households were those in which adult members reported that they collectively drank a minimum of two 75 cl bottles of wine a week; lived within a three-mile radius of a store that stocked the study wines in both 50 cl and 75 cl bottles; possessed a smartphone or equivalent device to provide evidence of the amount of wine consumed; did not take medications for which there was a recommendation against alcohol consumption; and did not have a serious mental illness or history of significant alcohol misuse. Data were collected between October 2018 and June 2019.

The quantity of wine routinely purchased by each household was derived from the baseline self-reported volume of wine consumed at home per week. For the purposes of the study this was multiplied by 3 to give an estimate of the amount needed for 3 weeks’ supply, and this volume was then rounded-up to the nearest multiple of 1.5 litres, to ensure that the same quantity could be purchased in either bottle size. Participating households then purchased this fixed volume of wine in the appropriate bottle size to consume during the intervention periods.

A total of 91 households were randomised to receive the 50 cl bottles first and 95 to receive the 50 cl bottles. Each intervention period lasted 14 days and was followed by a ‘usual behaviour’ period to allow households to finish the wine ordered during the intervention period before the crossover.

Households started the second intervention period, using the different bottle size but ordering the same amount of wine as the first intervention period, as soon as the wine from their first period had been, or was close to being, finished.

Of the 186 enrolled households 166 completed the study. After adjusting for prespecified covariates, 191.1 ml (95% CI: 42.03-339.2) or 4.5% (95% CI: 1.0-7.9%) more wine was consumed in the 14-day period from 75 cl bottles than from 50 cl bottles. Consumption was 5.8% faster (95% CI: –10.9 to – 0.4%) from 75 cl bottles than from 50 cl bottles.

The study authors conclude: ‘Consuming wine at home from 50 cl bottles compared with 75 cl bottles may reduce both the amount consumed and the rate of consumption.’

They add that: ‘Further studies are needed to assess the sustainability of the effect of smaller wine bottles on consumption beyond the time period assessed in the current study, to assess whether effects are maintained over time.’

Alcohol consumption is a major contributor to premature death and disease globally, with consequences for physical health, mental health and personal behaviour.

The winter holiday season is associated with increased alcohol consumption, and a range of potential harm.^2,3 It is possible that the impact of alcohol consumption on interpersonal behaviour may have additional risks during the current COVID-19 pandemic. Findings that help GPs suggest effective ways for patients to moderate alcohol consumption are welcome.