Randomised clinical trial: gut microbiome biomarkers are associated with clinical response to a low FODMAP diet in children with the irritable bowel syndrome

Summary Background A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet can ameliorate symptoms in adult irritable bowel syndrome (IBS) within 48 h. Aim To determine the efficacy of a low FODMAP diet in childhood IBS and whether gut microbial composition and/or metabolic capacity are associated with its efficacy. Methods In a double‐blind, crossover trial, children with Rome III IBS completed a 1‐week baseline period. They then were randomised to a low FODMAP diet or typical American childhood diet (TACD), followed by a 5‐day washout period before crossing over to the other diet. GI symptoms were assessed with abdominal pain frequency being the primary outcome. Baseline gut microbial composition (16S rRNA sequencing) and metabolic capacity (PICRUSt) were determined. Metagenomic biomarker discovery (LEfSe) compared Responders (≥50% decrease in abdominal pain frequency on low FODMAP diet only) vs. Nonresponders (no improvement during either intervention). Results Thirty‐three children completed the study. Less abdominal pain occurred during the low FODMAP diet vs. TACD [1.1 ± 0.2 (SEM) episodes/day vs. 1.7 ± 0.4, P