Moderate alcohol intake in non-alcoholic fatty liver disease: To drink or not to drink?

Abstract

Nonalcoholic fatty liver disease (NAFLD) is defined by hepatic steatosis in the presence of alcohol intake within safe limits, defined by guidelines of scientific associations (usually 20 g or 2 units/day in women, 30 g or 3 units in men). The diagnosis is usually followed by medical counseling of total abstinence, in order to prevent disease progression. This policy has been challenged by epidemiological studies, suggesting that the risk of liver disease and disease progression is lower in modest drinkers than in total abstainers. We revised the literature on the effects of modest alcohol intake on disease burden. Epidemiological data may suffer from several potential biases (recall bias for retrospective analyses, difficulties in the calculation of g/day), limiting their validity. Prospective data suggest that NAFLD patients with regular alcohol intake, although within the safe thresholds, are at higher risk of liver disease progression, including hepatocellular carcinoma; a detrimental effect of modest alcohol drinking is similarly observed in liver disease of viral etiology. Alcohol intake is also a risk factor for extrahepatic cancers, particularly breast, oral, and pharyngeal cancers, with gender difference and no floor effect, which outweigh the possible beneficial effects on cardiovascular system, also derived from retrospective studies. Finally, the negative effects of the calorie content of alcohol on dietary restriction and weight loss, the pivotal intervention to reduce NAFLD burden, should be considered. In summary, the policy of counseling NAFLD patients for alcohol abstinence should be maintained.