Epidemiological studies often report better heath in moderate drinkers compared with abstainers. Observed first in studies of incidence of myocardial infarction,1 the “J shaped curve” (describing the graphical appearance of health measures plotted against consumption) reappears in studies of diabetes, stroke, and even chronic widespread pain.2 As methods of investigating the association between alcohol and health are refined, however, the size of the apparent benefits reduces substantially.3 Studies using “Mendelian randomisation,” purportedly impervious to confounding or reverse causality, do not support the original claim that moderate drinking improves cardiovascular health.4......