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.