Gut microbiota changes as a risk factor for obesity.

Abstract The number of obese people in recent decades is increasing significantly. Among the many aspects of obesity in the last decade, the role and importance of changes in the gut microbiota (GM) attracts special attention. The aim of the review was to analyze the results of studies, focused on the role of gut microbiota in the obesity development. Screening was conducted on 33 researches, which examined the role of the gut microbiota balance in the development of obesity. Among them, 13 studies were selected for more detailed analysis. Obesity revealed typical changes in GM: an increase in the number of microbes of the genus Firmicutes and a decrease in the number of microbes of the genus Bacteroeidetes, which is particularly vividly demonstrated by studies of rodents. In obese mice, the microfamilies of the genus Firmicutes account for 80% of all GM (in control animals 60%), and the number of microorganisms of the genus Bacteroeidetes decreases by half (from 40 to 20%), compared to mice with normal weight. Despite the complexity of the question of the relationship between GM and obesity, the totality of the data received, especially the results of experimental studies, affirm the thesis that changes in GM may contribute to the development of obesity.