Last reviewed · How we verify

NCT04542018

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

Completed NA Results posted Last updated 30 July 2025
What this trial tests

NA trial testing a low FODMAP diet for 4 weeks in Irritable Bowel Syndrome in 48 participants. Completed in 15 May 2024.

Timeline
3 August 2020
Primary endpoint
15 May 2024
15 May 2024

Quick facts

Lead sponsorUniversity of Michigan
PhaseNA
StatusCompleted
Study typeINTERVENTIONAL
Allocationna
Designsingle group
Maskingnone
Primary purposebasic science
Enrollment48
Start date3 August 2020
Primary completion15 May 2024
Estimated completion15 May 2024
Sites2 locations across United States

Drugs / interventions tested

Conditions studied

Sponsor

University of Michigan

Who can join

Adults 18 to 65, any sex, with Irritable Bowel Syndrome. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Lactulose Mannitol Excretion Primary · 4 weeks

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

Baseline - Lactulose Excretion
GroupValue95% CI
Responders512.599 – 3456
Non-Responders394.5204 – 1982
4-Week - Lactulose Excretion
GroupValue95% CI
Responders456.860 – 1568
Non-Responders411221.4 – 992.5
Baseline - Mannitol Excretion
GroupValue95% CI
Responders413959600 – 430100
Non-Responders8682079040 – 207900
4-Week - Mannitol Excretion
GroupValue95% CI
Responders370302704 – 83356
Non-Responders5482511314 – 500480
Changes in Epithelial Permeability - Tight Junction Gene Expression Secondary · 4 weeks

Changes in tight junction (TJ) gene expression in colonic biopsies before and after low FODMAP diet Gene expression of Tight junction proteins were normalized to that of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH).

Baseline - ZO-1
GroupValue95% CI
Responders.9.1 – 3.5
Non-Responders.7.1 – 1
4-week - ZO-1
GroupValue95% CI
Responders1.4.3 – 4.8
Non-Responders1.1.2 – 3.2
Baseline - JAM-A
GroupValue95% CI
Responders0.90.03 – 2.6
Non-Responders0.50.1 – 1.3
4-week - JAM-A
GroupValue95% CI
Responders20.2 – 7.2
Non-Responders1.30.1 – 3.3
Baseline - Occludin
GroupValue95% CI
Responders0.90.1 – 3
Non-Responders0.60.1 – 1.1
4-week - Occludin
GroupValue95% CI
Responders1.30.1 – 4.8
Non-Responders0.80.1 – 2.1
Baseline - Claudin-1
GroupValue95% CI
Responders0.60.01 – 3.8
Non-Responders0.50.1 – 3.7
4-week - Claudin-1
GroupValue95% CI
Responders1.10.04 – 3.7
Non-Responders0.90.1 – 2.5
Changes in Epithelial Permeability - Quantitative Tight Junction Immunostaining Secondary · 4 weeks

Changes in Quantitative tight junction immunostaining of tight junctions in colonic biopsies before and after low FODMAP diet Data is reported as ratio of TJ proteins to NA-K ATPase.

Baseline - ZO-1
GroupValue95% CI
Responders0.065790.008542 – 0.3880
Non-Responders0.037030.01876 – 0.07138
4-week - ZO-1
GroupValue95% CI
Responders0.073300.01938 – 0.3061
Non-Responders0.050630.04520 – 0.07585
Baseline - JAM-A
GroupValue95% CI
Responders0.074930.01628 – 0.2034
Non-Responders0.084370.02690 – 0.09409
4-week - JAM-A
GroupValue95% CI
Responders0.091490.02220 – 0.3186
Non-Responders0.072670.05500 – 0.09367
Baseline - Occludin
GroupValue95% CI
Responders2.6230.6874 – 16.95
Non-Responders3.8342.624 – 9.378
4-week - Occludin
GroupValue95% CI
Responders5.5290.7352 – 13.05
Non-Responders5.5332.724 – 16.5
Baseline - Claudin-1
GroupValue95% CI
Responders6.5420.5603 – 20.69
Non-Responders10.407.514 – 12.13
4-week - Claudin-1
GroupValue95% CI
Responders11.221.696 – 17.38
Non-Responders9.2181.108 – 20.86
Changes in Stool Microbiome - Alpha Diversity Secondary · 4 weeks

Changes in relative abundance of bacteria before and after low FODMAP diet. Alpha diversity was measured as number of Amplicon Sequence Variant (ASV) measured in the specimen.

Baseline - Alpha Diversity
GroupValue95% CI
Responders649.087± 160.1794
Non-Responders532.75± 153.69
4-week - Alpha Diversity
GroupValue95% CI
Responders599.7391± 159.1749
Non-Responders608.5± 182.12
Changes in Stool Microbiome - Beta Diversity Secondary · 4 weeks

Changes in relative abundance of bacteria before and after low FODMAP diet. For the beta diversity, an analysis of similarities (ANOSIM)test based on Bray-Curtis distances is the best measure if the communities were different. The ANOSIM R statistic gives the scale of difference. ANOSIM R ranges from -1 to 1, where 1 means there is most interparticipant similarity within the group compared with between the different groups, and where -1 means there is least interparticipant similarity within the group compared with between the different groups. A value close to 0 indicates no significant diffe

GroupValue95% CI
Responders-0.03722
Non-Responders-0.2708
Immunohistochemistry for Mast Cells Secondary · 4 weeks

Number of mast cells in sample after immunohistochemistry were counted.

Baseline - Mast Cell Count
GroupValue95% CI
Responders235.2 – 42.5
Non-Responders26.518.7 – 27.2
4-Week - Mast Cell Count
GroupValue95% CI
Responders14.55.4 – 25.8
Non-Responders11.59.5 – 24.2
Gastrointestinal Patient Reported Outcomes Measurement Information System (PROMIS) Secondary · 4 weeks

PROMIS scales of Belly pain (5a) and diarrhea (6a) will be administered to assess the severity of belly pain and diarrhea in our patients. PROMIS Belly pain questionnaire and PROMIS diarrhea questionnaire have five and six questions, respectively, which assess symptom severity on a 5 point Likert scale. 50 indicates the general population mean with a standard deviation of 10. Higher T-scores on these questionnaires refer to more severe gastrointestinal symptoms. PROMIS belly pain asks how often did you have belly pain, severity of belly pain, interference with activities, bothersomeness and d

Baseline - Belly Pain
GroupValue95% CI
Responders63.6± 6.2
Non-Responders64.1± 5.1
Intervention Recipients Who Did Not Complete the Trial63.7± 6.4
4-week - Belly Pain
GroupValue95% CI
Responders47.1± 9.4
Non-Responders60.8± 3.1
Baseline - Diarrhea
GroupValue95% CI
Responders61.2± 10.8
Non-Responders49.1± 8.3
Intervention Recipients Who Did Not Complete the Trial61.3± 5
4-week - Diarrhea
GroupValue95% CI
Responders55.8± 8.3
Non-Responders55.6± 8.4
Intervention Recipients Who Did Not Complete the Trial0± 0
Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) - 4-Week Secondary · 4 weeks

Measure Description: IBS-SSS is a scale for assessing overall IBS symptom severity. It includes 5 questions concerning symptoms over the past 10 days: average severity of abdominal pain, # of days with abdominal pain, average severity of abdominal distension or bloating, satisfaction with bowel habits, and the overall interference in their quality of life from these symptoms. Questions are scored on a 0-100 scale and are summed to a total score between 0-500. Lower scores indicate lower symptom severity. Participants were separated into arms based on the change in their responses from baselin

GroupValue95% CI
Responders87.7± 84.8
Non-Responders235.4± 72.12

Adverse events — posted to ClinicalTrials.gov

Time frame: 4 weeks. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Responders
Serious: 0/34 (0%)
Deaths: 0/34
Non-Responders
Serious: 0/8 (0%)
Deaths: 0/8
Intervention Recipients Who Did Not Complete the Trial
Serious: 0/6 (0%)
Deaths: 0/6
Other adverse events (3 terms — click to expand)

ReactionSystemRespondersNon-RespondersIntervention Recipients Wh…
Post-Vaccination Stomach Pain and DiarrheaGastrointestinal disorders
Ankle fractureInjury, poisoning and procedural complications
COVID-19Infections and infestations

Data from ClinicalTrials.gov NCT04542018 adverse events section.

Sponsor's own description

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.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

  1. 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.
    Gao J, Lee AA, Abtahi S, Turner JR, et al · · 2026 · cited 7× · PMID 40749856 · DOI 10.1053/j.gastro.2025.07.016

Verify or expand the search:

Other recruiting trials for Irritable Bowel Syndrome

Currently open trials in the same condition.

Other University of Michigan trials

Trials by the same sponsor.

Verify against primary sources

Data sources for this page

Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT04542018.

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing