Fatty liver disease and gut microbiota: A comprehensive update

Nonalcoholic fatty liver disease (NAFLD) is the accumulation of fat in the liver in the absence of secondary causes. NAFLD is a multifactorial disease that results from the interaction of genetic predisposition and metabolic, inflammatory and environmental factors. Among these factors, dysregulation of gut microbiome has been linked to the development of fatty liver disease. The microbiome composition can be modified by dietary habits leading to gut microbiome dysbiosis, especially when a diet is rich in saturated fats, animal products and fructose sugars. Different species of bacteria in the gut metabolize nutrients differently, triggering different pathways that contribute to the accumulation of fat within the liver and triggering inflammatory cascades that promote liver damage. In this review, we summarize the current understanding of the roles of gut microbiota in mediating NAFLD development and discuss possible gut microbiota-targeted therapies for NAFLD. We summarize experimental and clinical evidence, and draw conclusions on the therapeutic potential of manipulating gut microbiota to decrease the incidence and prevalence of fatty liver disease.