Metabolic dysfunction-associated steatotic liver disease and the gut microbiome: a narrative review of pathophysiology, diagnostic value, and therapeutic approaches

Purpose: This review summarizes current evidence on the role of the gut microbiome in the pathogenesis, diagnosis, and treatment of metabolic dysfunction-associated steatotic liver disease (MASLD), with particular emphasis on the gut–liver axis and microbiome-based therapeutic approaches.Current concepts: MASLD is among the most prevalent chronic liver diseases worldwide and is strongly associated with cardiometabolic risk factors. Evidence from clinical and preclinical studies indicates that gut microbial dysbiosis contributes to the development and progression of MASLD through increased intestinal permeability, endotoxin translocation, and altered production of microbiota-derived products and metabolites, including lipopolysaccharide, bile acids, short-chain fatty acids, trimethylamine N-oxide, and tryptophan metabolites. Interactions between host genetic susceptibility and the gut microbiome may further influence disease pathogenesis. Compared with healthy individuals, patients with MASLD show reduced microbial diversity and characteristic changes in bacterial, viral, and fungal communities that correlate with disease severity. Shotgun metagenomics and multi-kingdom analyses have identified microbiome-based signatures with potential value as noninvasive diagnostic biomarkers. Therapeutic strategies targeting the gut microbiome, including dietary interventions, probiotics, synbiotics, and fecal microbiota transplantation, have also shown promise, although evidence of histological improvement remains limited.Discussion and conclusion: The gut microbiome plays an important role in MASLD and may inform biomarker development and therapeutic targeting. Future research should prioritize standardized, multicenter, prospective studies and precision-medicine approaches that integrate microbial, genetic, and metabolic profiles to support the development of clinically applicable microbiome-based strategies.