Alcohol, stroke and coronary heart disease. Are there anti-oxidants and pro-oxidants in alcoholic beverages that might influence the development of atherosclerotic cardiovascular disease?

Anti-oxidant effects of polyphenolic flavonoid compounds found in alcoholic beverages, especially red wine, have been proposed to mediate, at least in part, protective effects of regular light-to-moderate alcohol use against stroke and coronary artery disease. The proposed mechanism is through the quenching of free radicals decreasing the oxidative modification of low-density lipoprotein cholesterol particles and hence reducing their atherogenicity. In this review, the extent and limitations of the evidence in support of such a hypothesis are outlined. In particular, the paucity of epidemiological evidence linking dietary flavonoids to stroke and coronary artery disease is highlighted. The competing notion that alcohol itself has direct and indirect pro-oxidant and pro-atherogenic effects is canvassed, and the limitations of the in vitro rather than in vivo nature of much of the evidence linking red wine polyphenolics to reduced lipid peroxidation and other relevant biological effects is discussed. Within this framework of current epidemiological evidence together with the results of basic laboratory studies, the conclusion at present is that while we may continue to speculate that there are anti-oxidants and pro-oxidants in alcoholic beverages that influence the development of atherosclerotic cardiovascular disease, this cannot yet be considered as an established scientific fact.