A Novel, IBS-Specific IgG ELISA-Based Elimination Diet in Irritable Bowel Syndrome: A Randomized, Sham-Controlled Trial

Gastroenterology. 2025 Jun;168(6):1128-1136.e4. doi: 10.1053/j.gastro.2025.01.223. Epub 2025 Jan 31.

Abstract

Background & aims: Personalized dietary therapies for irritable bowel syndrome (IBS) are needed and an immunoglobulin (Ig)G-antibody-based elimination diet presents a potential solution. However, existing studies have serious methodological limitations. This study aimed to assess the efficacy of an elimination diet by using a novel IBS-specific IgG assay.

Methods: We conducted a randomized, double-blind, sham-controlled trial enrolling subjects with IBS from 8 centers. Subjects positive for ≥1 food on an 18-food IgG assay and an average daily abdominal pain intensity score between 3.0 and 7.5 on an 11.0-point scale during a 2-week run-in period were randomized to either an experimental antibody-guided diet or sham diet for 8 weeks. The primary outcome was a ≥30% decrease in abdominal pain intensity for ≥2 of the last 4 weeks of the treatment period.

Results: Among 238 randomized subjects with IBS, 223 were included in the modified intention-to-treat analysis. A significantly greater proportion of subjects in the experimental diet group met the primary outcome than those in the sham diet group (59.6% vs 42.1%, P = .02). Subgroup analysis revealed that a higher proportion of subjects with constipation-predominant IBS and IBS with mixed bowel habits in the experimental diet group met the primary endpoint vs the sham group (67.1% vs 35.8% and 66% vs 29.5%, respectively).

Conclusions: Subjects on an IgG-guided elimination diet were more likely to achieve the primary endpoint than those on a sham elimination diet. Subgroup analysis suggests a more robust benefit for subjects with constipation-predominant IBS and IBS with mixed bowel habits. This highlights the potential effectiveness of a personalized elimination diet based on a novel IBS-specific IgG assay. A larger study is warranted to validate these observations. (ClinicalTrials.gov, Number NCT03459482.).

Keywords: Bloating; Bowel Habits; Disorders of Gut-Brain Interaction; Functional Bowel Disorder; IBS With Diarrhea; Precision Medicine.

Publication types

  • Randomized Controlled Trial
  • Multicenter Study

MeSH terms

  • Abdominal Pain / diet therapy
  • Abdominal Pain / etiology
  • Abdominal Pain / immunology
  • Adult
  • Aged
  • Double-Blind Method
  • Elimination Diets
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Humans
  • Immunoglobulin G* / blood
  • Immunoglobulin G* / immunology
  • Irritable Bowel Syndrome* / blood
  • Irritable Bowel Syndrome* / diagnosis
  • Irritable Bowel Syndrome* / diet therapy
  • Irritable Bowel Syndrome* / immunology
  • Male
  • Middle Aged
  • Treatment Outcome
  • Young Adult

Substances

  • Immunoglobulin G

Associated data

  • ClinicalTrials.gov/NCT03459482