Inulin Fiber Trial in Obese Thai Children: Results Posted

TL;DR: A completed randomized controlled trial in 165 obese Thai children (ages 7–15) tested whether the prebiotic fiber inulin shifts gut bacteria and body fat over six months. Results are posted on the registry; this is a single, modest-sized pediatric study, not proof of a weight-loss or longevity benefit.

What this inulin trial set out to test

Inulin is a type of dietary fiber found naturally in foods like chicory root, onions and garlic. It acts as a prebiotic — meaning it is not digested by us but instead feeds beneficial bacteria in the large intestine. Researchers at Chulalongkorn University wanted to know whether adding inulin to a child's diet would change the makeup of the gut microbiota (the community of microbes living in the intestine) and affect measures related to obesity.

The condition under study was childhood obesity, defined here by a Body Mass Index (BMI) at or above the median plus two standard deviations for age. All 165 participants were obese Thai children aged 7 to 15; healthy-weight volunteers were not enrolled.

How was the study designed?

This was a randomized interventional trial with three parallel arms over a six-month period:

• Group A: daily inulin (the prebiotic intervention)
• Group B: an isocaloric maltodextrin placebo (a comparison powder with similar calories but no prebiotic effect)
• Group C: dietary fiber advice matched to age-appropriate recommendations

Randomizing children into these groups helps ensure the arms are comparable, so any differences at six months are more likely due to the intervention than to chance. The study was not assigned a drug-trial phase because inulin is a food-based fiber rather than a new medicine.

What did the posted results measure?

The trial's primary outcome was the abundance of *Bifidobacterium* — a group of gut bacteria often associated with fiber fermentation — reported as a Z-score at baseline and at month six. Results comparing inulin, maltodextrin and dietary-fiber arms are now posted on ClinicalTrials.gov.

Alongside the primary microbiome measure, the posted results also report:

• Change from baseline in Fat Mass Index (FMI) and Fat-Free Mass Index (FFMI) at six months — measures of how much of the body is fat versus lean tissue
• Change from baseline in children's eating behaviors at six months
• Change from baseline in interleukin-15 (an immune-signaling protein) at six months, in the inulin group

The registry posts these outcome measures rather than a plain-language verdict. Because specific effect sizes are best read directly from the source, interested readers and clinicians should consult the posted data tables. Body composition here was tracked with body composition analysis, a method also used in adult metabolic assessments.

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