Gut microbiome in non-alcoholic fatty liver disease

Abstract

Abstract The human gut microbiome is composed of communities of bacteria, viruses and fungi. Bacteria live in each part of digestive tract, increasing their density and changing composition in distal parts. The composition of gut microbiome mainly depends on method of childbirth, age, gender, diet, stress, infections, alcohol intake, diurnal variation, smoking, drugs (antibiotics), physical activity. Dysbiosis is defined as an imbalance or maladaptation in the gut microbial community. This imbalance favors many pathological states and it could be due to some diseases. Non-alcoholic fatty liver disease (NAFLD) has become increasingly common in parallel with the increasing prevalence of obesity and other components of the metabolic syndrome. In year 2020, a more comprehensive new definition of NAFLD was proposed – fatty liver disease associated with metabolic dysfunction (MAFLD). NAFLD/MALFD will become the major form of chronic liver disease in adults and children and could become the leading indication for liver transplantation within a decade. An increased level of Bacteroidetes and decreased level of Firmicutes is observed in fatty liver disease. This imbalance favors the collection of energy and insulin resistance. The prevention and treatment of dysbiosis in NAFLD/MAFLD is essential. The purpose of this review is an understanding related to the dysbiosis and non-alcoholic fatty liver disease in order to help physicians of different specialties in their clinical practice because of growing in population patients with metabolic syndrome and liver steatosis.