Resting energy expenditure and gut microbiota in obese and normal weight subjects.

OBJECTIVES It is suggested that gut microbiota play a role in the pathogenesis of obesity enhancing energy utilization from digested food. The influence of gut microbiota on resting energy expenditure (REE) has not been evaluated yet. AIM The aim of the study is to assess the composition on gut microbiota and its association with REE in obese and normal weight subjects. SUBJECTS AND METHODS REE measurement and semi-quantitative analysis of gut microbiota composition in aerobic and anaerobic conditions were performed in 50 obese and 30 normal weight subjects without concomitant diseases. RESULTS A count of bacterial colony was greater in obese than in normal weight subjects. However, the proportion of Bacteroides spp. and Firmicutes was similar in both study groups. A positive correlation between REE (kcal/d) and total bacterial count (r = 0.26, p < 0.05), as well as between REE and the percentage of Firmicutes (r = -0.24, p < 0.05) was found. The multiple regression analysis did not prove an independent impact of total bacterial as well as Bacteroides spp. and Firmicutes counts on REE. CONCLUSIONS The composition of gut microbiota is not associated with the level of resting energy expenditure. The proportion of Bacteroides and Firmicutes in gut microbiota is not related to body mass.