Effects of Low FODMAP Diet on Colonic Epithelial Physiology in Diarrhea-predominant Irritable Bowel Syndrome

NCT04542018 | Completed Results

• 2 other identifiers: HUM00166423K23DK129327
• Study Type: interventional
• Target: 48
• Locations: 1 country
• Sites: 2

Brief Summary

This research is studying whether changing an individual's diet may have an impact as a treatment or outcome for Irritable Bowel Syndrome (IBS). This research will show if diet might play a role in triggering changes that may cause IBS. This study is being done to learn if a low FODMAP (fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols) diet causes changes in the colon lining which mediates improvement in IBS symptoms.

Conditions

Irritable Bowel Syndrome

Outcome Measures

Primary Outcomes (1)

• Lactulose Mannitol Excretion

  Changes in cumulative excretion of lactulose and mannitol in timed urine collection before and after low FODMAP diet measured during 8-24h

  4 weeks

Secondary Outcomes (6)

• Changes in Epithelial Permeability - Tight Junction Gene Expression

  4 weeks

• Changes in Epithelial Permeability - Quantitative Tight Junction Immunostaining

  4 weeks

• Changes in Stool Microbiome - Alpha Diversity

  4 weeks

• Changes in Stool Microbiome - Beta Diversity

  4 weeks

• Immunohistochemistry for Mast Cells

  4 weeks

Other Outcomes (1)

• Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) - 4-Week

  4 weeks

Study Arms (1)

Study patients with IBS-D

EXPERIMENTAL

Patients with diarrhea-predominant IBS who will undergo a low FODMAP diet for 4 weeks

Other: a low FODMAP diet for 4 weeks

Interventions

a low FODMAP diet for 4 weeks OTHER

low FODMAP diet for 4 weeks

Study patients with IBS-D

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Normal serum studies including serum tissue-transglutaminase antibodies, thyroid stimulating hormone levels, C-reactive protein or fecal calprotectin, complete blood count since the onset of symptoms.
• Normal stool studies including, ova and parasites since the onset of symptoms
• IBS-SSS score of ≥175 at the end of the 7-day screening period
• In case of presence of any alarm features and/or elevated inflammatory markers (C-reactive protein or fecal calprotectin), patients will be eligible if they have been excluded for inflammatory bowel disease with colonoscopy in the last one year.

You may not qualify if:

• individuals already on a LFD or other dietary restriction such as gluten free diet within the past 6 months
• individuals with any known food allergy or insulin-dependent diabetes
• known history of celiac disease, inflammatory bowel disease or microscopic colitis
• prior small bowel or colonic surgery or cholecystectomy
• pregnant patients
• Antibiotics in the past 3 months
• Those who regularly use mast cell stabilizers or anti-histaminic or non-steroidal anti-inflammatory agents (NSAIDs) excluding daily baby aspirin or steroids or bile-acid binder.

Sponsors & Collaborators

• University of Michigan: lead
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): collaborator

Study Sites (2)

Beth Israel Deaconess Medical Center

Boston, Massachusetts, 02215, United States

Location

University of Michigan

Ann Arbor, Michigan, 48109, United States

Location

Related Publications (1)

• Gao J, Lee AA, Abtahi S, Turner JR, Grover M, Schmidt A, Schmidt TM, Nee JW, Iturrino J, Lembo A, Chey WD, Wiley JW, Singh P. Low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols Diet Improves Colonic Barrier Function and Mast Cell Activation in Patients With Diarrhea-Predominant Irritable Bowel Syndrome: A Mechanistic Trial. Gastroenterology. 2026 Jan;170(1):132-147. doi: 10.1053/j.gastro.2025.07.016. Epub 2025 Jul 30.

  PMID: 40749856 DERIVED

MeSH Terms

Conditions

Irritable Bowel Syndrome

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases

Results Point of Contact

• Title: Prashant Singh, MBBS
• Organization: University of Michigan

singhpr@med.umich.edu

734-647-1191

Study Officials

• Prashant Singh

  University of Michigan

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Patients with diarrhea predominant IBS (IBS-D) will undergo 4 weeks of low FODMAP diet. Urine, blood, stool, and colon biopsies will be collected before and after the diet to assess changes in gut physiology.

Study Record Dates

• First Submitted: September 1, 2020
• First Posted: September 9, 2020
• Study Start: August 3, 2020
• Primary Completion: May 15, 2024
• Study Completion: May 15, 2024
• Last Updated: July 30, 2025
• Results First Posted: July 30, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)