Moderate alcohol consumption and the risk of cardiovascular disease

Abstract

We read with interest the results of the fifth examination cycle of the Framingham Offspring Study concerning plasma concentrations of the cardiovascular disease risk factor total homocysteine (tHcy), as reported by Jacques et al (1) in the Journal. The authors concluded that different dietary and lifestyle factors— such as intakes of vitamin B-6, riboflavin, alcohol, and caffeine; smoking; and hypertension—influence circulating tHcy concentrations. We wish to emphasize the influence of alcohol consumption on concentrations of plasma homocysteine. Pathologically raised concentrations of plasma homocysteine have been reported in patients with chronic alcoholism (2, 3) and during alcohol withdrawal (4), whereas normal concentrations are found in alcohol-intoxicated patients who are not alcohol dependent (5). It has been proposed that ethanol-induced hyperhomocysteinemia may be a significant factor in the increased incidence of coronary artery disease and stroke related to high alcohol consumption (6, 7). However, the results of various epidemiologic studies suggest that moderate alcohol intakes of the equivalent of 2 drinks/d (20–40 g alcohol/d) of any kind of alcohol, especially red wine, are associated with a reduced incidence of coronary artery disease, a phenomenon referred to as the French paradox (8). In a previous study (9), we examined whether mild-to-moderate alcohol consumption—referred to as social drinking—changes plasma tHcy concentrations. We compared the plasma concentrations of abstinent individuals with those of non-alcoholdependent social drinkers who consumed 30 g alcohol/d over a period of 6 wk. The social drinkers were further divided into 3 groups according to the source of alcohol consumed (beer, red wine, or spirits). We found abstinent individuals to have significantly lower concentrations of endogenous tHcy than did consumers of beer, red wine, or spirits. Additionally, consumers of red wine and spirits had pathologically raised plasma tHcy concentrations at the end of the observation period, whereas the concentrations in beer consumers were significantly raised but still within the normal range (9). These results support Jacques et al’s observation that lifestyle habits, especially the consumption of alcohol, significantly influence concentrations of plasma tHcy. In contradiction to the cardioprotection of alcohol suggested by the French paradox, we postulate that the elevated concentrations of tHcy in subjects with a social drinking pattern of regular, moderate alcohol intake are a risk for cardiovascular disease. Nevertheless, further investigations and controlled studies are needed to clarify the possible association between social drinkers’ alcohol consumption, homocysteine concentrations, and the risk of cardiovascular diseases.