Inulin Supplementation Altered Gut Microbiota and Microbial Functional Pathways in Children With Obesity: A Randomized, Double-Blinded Placebo-Controlled Study

Objectives: Gut dysbiosis induces host-microbe interactions that might worsen obesity. Gut microbiota manipulation by supplementation of inulin may reverse metabolic abnormalities and improve obesity. The objective was to determine whether inulin supplementation improved intestinal microbiota and microbial functional pathways in children with obesity. The relationships of the changes in gut microbiota with clinical and metabolic features were also assessed. Methods: Children with BMI > median+2SDs according to the WHO reference were recruited to a randomized controlled study. The participants aged 7-15 years were assigned to inulin (intervention), maltodextrin (placebo), and dietary fiber advice groups. All received monthly follow-up for 6 months with the same conventional advice. Fecal samples were collected for gut microbiome analysis by 16S rRNA sequencing. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was performed to infer microbial functional pathways. Results: One hundred and forty-three children were evaluated. A significant increase in alpha-diversity in the inulin group was found. Inulin supplementation substantially enhanced Bifidobacterium, Blautia, Megasphaera, and several butyrate-producing bacteria, including Agathobacter, Eubacterium coprostanoligenes, and Subdoligranulum, compared to the others. Functional pathways of proteasome and riboflavin metabolism in the inulin group were significantly different from the placebo group. The relationships between the changes in gut microbiota and the changes in clinical or metabolic features in 6 months were notably found in the inulin group compared to the others. Conclusions: Inulin supplementation significantly promoted bacterial diversity and substantially enhanced Bifidobacterium, Blautia, Megasphaera, and butyrate-producing bacteria. Functional pathways and the relationships of microbes with clinical and metabolic parameters modulated by inulin showed predominantly different patterns from the others, indicating inulin might establish the favorable connections of the gut microbiota with host physiology. Inulin supplementation could be a strategic treatment to restore the balance of gut microbiota and beneficially regulate their functions in childhood obesity. Funding Sources: Ratchadapiseksompotch Fund NSTDA Fund.