Level 2: Mid-level evidence
Moderate alcohol consumption has previously been associated with decreased cardiovascular risk (BMJ. 2006;332:1244-1248) and decreased overall mortality (Arch Intern Med. 2006;166:2437-2445) in observational studies. A recent study assessed the effects of alcohol on weight gain in a cohort of 19,220 women (mean age 54 years) who had normal BMI (18.5-25) at baseline and were followed for 13 years (Arch Intern Med. 2010;170:453-461). All the women were free of cardiovascular disease, cancer, and diabetes at baseline. There was a dose-dependent reduction in the risk of becoming overweight or obese associated with drinking up to 30 g of alcohol (about two drinks) per day compared with no alcohol consumption. For 15-30 g/day, the adjusted risk ratio was 0.86 (95% CI 0.8-0.92) for becoming overweight and 0.43 (95% CI 0.34-0.56) for becoming obese. As little as 5 g/day (two drinks per week) was found to lower risk. There was no additional risk reduction associated with consuming >40 g/day. In an analysis of different types of alcohol consumed, red wine was associated with the greatest risk reduction.