Effect of alcohol on endothelial function in healthy subjects

While studies have shown that red wine improves endothelial function, the effect of pure alcohol, the common denominator of all alcoholic beverages, on endothelial function has not been defined. The effect of oral intake of alcohol (one ounce--a dose corresponding to two drink equivalents) on flow-mediated dilatation of the brachial artery was studied in 12 healthy subjects using high-resolution ultrasonography according to a randomized, sham procedure-controlled, single-blind protocol. Alcohol produced a significant vasodilatation of the brachial artery at resting conditions. Furthermore, it led to a significant increase of the brachial artery diameter at reactive hyperemia; however, the percentage flow-mediated dilatation did not change. This study shows, for the first time, that acute moderate intake of alcohol has a potent dilating effect on large arteries both at resting and at reactive hyperemic conditions, without affecting flow-mediated dilatation as a percentage. This may be useful for explaining the divergent effect of different alcoholic beverages on endothelial function and provides valuable insight into the mechanisms involved in the vascular effects of alcohol.