Role of Gut-Liver Axis in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease has emerged as a significant global health problem, mainly due to the increasing prevalence of obesity and metabolic syndrome. The gut microbiota plays an essential role in the development of NAFLD through the gut-liver axis. Dysbiosis of the GM is associated with the pathogenesis of NAFLD. Dietary choices and other lifestyle factors influence the composition of the GM and contribute to the development of NAFLD. At the phylum level, individuals with NAFLD show an increased level in Actinobacteria and Firmicutes, while Verrucomicrobia, Thermus, Proteobacteria, Lentiphaerae, and Fusobacteria are found to be decreased. Several genera, including Faecalibacterium and Akkermansia, exhibit alterations in NAFLD and are linked to disease progression. Modulating the GM through prebiotics, probiotics, or fecal microbiota transplantation represents a promising therapeutic strategy for NAFLD. This review summarizes the current understanding of GM changes in NAFLD, focusing on findings from both human and animal studies.