Gut Microbiota Diversity in Lean Athletes Is Associated with Positive Energy Balance

Abstract

Introduction: In contrast to obesity, little is known about the human lean phenotype associated with gut microbiota composition. Objective: We aimed to investigate whether the bacterial composition of lean athletes with a positive energy balance differs from the equal-calorie food group. Methods: Twenty-four male participants were included in this cross-sectional study: lean athletes with a positive energy balance (LA, n 12) and control group athletes (CTRLs, n 12). Nutritional data, resting and total energy expenditure, and body composition were determined. DNA was extracted from stool samples and subjected to 16S rRNA gene analysis. Results: We found 7 differentially abundant bacterial taxa between the LA and CTRL groups. Of those, 5 were significantly less abundant and 2 were enriched in the LA group. The following categories significantly associated with the community structure were identified: body fat parameters, BMI, energy intake and expenditure, oxygen consumption, and respiratory exchange ratio. Conclusions: Although we are far from a detailed interpretation of lean human body maintenance, the primary findings of our study suggest that gut microbial composition may be a factor influencing the regulation of weight gain in lean athletes with a positive energy balance.