Probiotics for dietary management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by an increase in fat content of liver cells, which is independent from alcohol intake. Here, we review the impact of microbiota and diet on the pathogenesis of NAFLD and the present knowledge on the effect of probiotics for dietary management of NAFLD. The major points are the following: (1) dietary preference of a high fructose and/or high fat diet seems to be associated with NAFLD. (2) Different microbial metabolites, including short chain fatty acids and ethanol, are associated with increased levels of lipogenesis. (3) Ethanol is metabolized to acetaldehyde resulting in increased oxidative stress and consecutively in liver injury. (4) Ethanol may also impair gut barrier function, which may enable translocation of lipopolysaccharides from Gram-negative bacteria and, hence, further promote low grade inflammation in liver tissue. (5) Beneficial gut microbiota may counteract the pathogenesis of NAFLD through displacement of NAFLD promoting microbes, reduction of overall microbial ethanol production, promotion of gut barrier function and suppression of inflammatory cascades. Therefore, selective probiotic strains with proven efficacy for NAFLD management and validated safety can be considered as a promising approach for NAFLD management.