Gut microbiota and nutritional interventions in alcohol-associated liver disease: Mechanisms and therapeutic advances

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality worldwide. Despite growing awareness of its burden, treatment options remain limited, with abstinence as the only widely accepted intervention. Recent research underscores the critical role of the gut-liver axis and nutritional status, particularly dietary protein, in modulating ALD pathogenesis and progression. This review aims to integrate current knowledge on the interplay between gut microbiota, dietary protein, and alcohol-induced liver injury, and to evaluate microbiota-targeted therapeutic strategies, including fecal microbiota transplantation (FMT), within this context. We examine how chronic alcohol intake reshapes the gut microbiome, impairs barrier function, and alters microbial metabolism. We discuss how dietary protein, based on source, quantity, and amino acid composition, influences microbial ecology and metabolite profiles, with plant and dairy proteins emerging as beneficial. The review also highlights advances in FMT, which shows promise in improving outcomes in severe alcoholic hepatitis. However, its efficacy is modulated by donor microbial composition and recipient compatibility, both of which may be influenced by diet. Furthermore, we address emerging evidence on the role of fungal and viral communities, which remain understudied contributors to ALD. Despite substantial progress, significant knowledge gaps persist. These include the need for clinical validation of preclinical findings, deeper exploration of nonbacterial microbiota, and a lack of personalized, nutrition-based interventions. Addressing these gaps through integrative, multiomic approaches will be essential to advancing precision therapeutics in ALD.