The association between gut microbiota and resting metabolic rate in overweight/obese women: a case-control study

When examining the underlying processes of obesity, evaluation of gut flora and energy homeostasis can be crucial since disruption of the normal gut microbiota community and energy imbalances are significant factors in the development of obesity. Therefore, this study aimed to compare the relative abundance of important obesity modulator gut microbiota (including Firmicutes, Bacteroidetes, Bifidobactrium spp., Lactobacillus spp., Bacteroides fragilis, Faecalibacterium prausnitzii, Akkermansia muciniphila, and Escherichia coli) in fecal samples of normometabilic and hypometabolic overweight/obese individuals.

This matched case-control study conducted on 36 healthy women aged 18-50 years old. An indirect calorimeter and impedance body analyzer were used to assess resting metabolic rate (RMR) and body composition, respectively. Dietary intake and physical activity were assessed using questionnaires. To determine the abundance of the abovementioned gut microbiota, quantitative polymerase chain reaction (qPCR) method was performed. Moreover, ELISA kits were used to assess leptin, ghrelin, and insulin hormones.

The results highlighted higher load of Firmicutes (p = 0.02), F. prausnitzii (p < 0.001), and B. fragilis (p = 0.02) in the normometabolic individuals compared to the hypometabolic ones. Besides, the positive correlation between the abundance of Firmicutes (β = 7.76 × 10^-1, p = 0.01), F. prausnitzii (β = 1.29 × 10^-5, p = 0.01), and B. fragilis (β = 4.13 × 10^-6, p = 0.04) with the RMR have been shown. Whereas the abundance of Bacteroidetes, A. muciniphila, Lactobacillus spp., Bifidobactrium spp., and E. coli showed no significant difference (p > 0.05) and no significant correlation with the RMR except Lactobacillus spp. (β = 1.73 × 10^-4, p = 0.01).

It seems that gut microbiota can be a potential target for refining host energy homeostasis and treating obesity and its consequences.