Gut microbiome as a risk factor of overweight and obesity

Overweight and obesity are a global medical and social problem. Current data indicate a significant role of the intestinal microbiome in the modulation of energy metabolism and the pathogenesis of obesity, while the regional features of the functional characteristics of a healthy microbiome remain poorly understood.

The aim is to study the features of the large intestine microbiome in middle–aged men living in the Magadan region, taking into account the variability of body mass index (BMI).

In the study, the qualitative and quantitative composition of the large intestine microbiome was assessed by PCR analysis in men permanently residing in the Magadan region. The participants were stratified into two groups according to the BMI value: those with normal body weight and those with overweight/obese.

The analysis of the occurrence index revealed significant intergroup differences in the composition of the microbiota: Enterococcus spp. was detected more often in men with a normal BMI than in the overweight sample (by 20 %) as well as Blautia spp. (by 20 %), Streptococcus spp. (by 27 %), Ruminococcus spp. (by 23 %), and Acinetobacter spp. (by 10%); on the contrary, Prevotella spp. was detected less frequently in this group (by 20 %). Bifidobacterium spp. was found to prevail in individuals with a normal BMI, whereas overweight individuals showed an increase in the proportion of the Bacteroidetes phylum and a decrease in the Firmicutes phylum, despite the growth of Lactobacillus spp., observed against the background of a slightly lower microbiological diversity of the large intestine.

The study revealed a clear association between changes in the intestinal microbiota in the two study groups and the nutritional characteristics typical for the "Western diet". The most pronounced dysbiotic disorders were observed in the overweight group, where a significant imbalance of macronutrients was detected involving deficiency of protein and dietary fiber against the excessive proportion of consumption of mono-disaccharides.

The revealed differences in the microbiota composition between people with normal weight and overweight confirm the possibility to use the microbiotic profile as an additional indicator of the obesity risk. The Study findings are consistent with current ideas about the impact exerted by a diet on intestinal microbiocenosis and also emphasize the need to further study the characteristics of a healthy microbiome in order to develop personalized approaches to improving the quality of life in northern populations.