Body Mass Index and Gut Microbiome: A Cluster-Randomized, Controlled, Pilot Feasibility Study

Background: Prebiotic fiber has been examined as a way to foster gut bacteria less associated with obesity. Tests of prebiotic fiber in reducing obesity have been conducted mainly in animals, adults, and Caucasians when the highest obesity rates are in African American and Latinx youth. Response to prebiotic fiber is determined by the pre-existing intestinal microbiota. The type of microbiota varies based on diet and physical activity (PA), so it is important to examine acceptability and response to prebiotic fiber in those most at risk for obesity. Methods: This cluster-randomized, controlled feasibility trial included an online program designed to improve diet and PA along with administration of a prebiotic fiber for 12 weeks in 123 students of 4th and 5th grade where 98% were eligible for free or reduced-fee lunch. Of these 56% were male; 71% Latinx; 15% African American; and 14% other. Results: Decrease in body fat (BF) was associated with higher pretest BF. Lower body mass index (BMI) was associated with decrease in fecal Tenericutes and increase in Actinobacteria. Conclusions: Prebiotic fiber can be helpful in supporting healthy weight, so inclusion in culturally congruent foods usually eaten by children from groups at high risk for obesity should be considered following additional studies. Determining those most responsive to prebiotic fibers can also permit individual recommendations for greater inclusion in usual diet choices. Clinical Trial Registration Number NCT05671731.