Irritable Bowel SyndromeNCT04542018
Effects of Low FODMAP Diet on Colonic Epithelial Physiology in Diarrhea-predominant Irritable Bowel Syndrome
A study testing a low FODMAP diet for 4 weeks in people with Irritable Bowel Syndrome, run by University of Michigan at 2 sites in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Irritable Bowel Syndrome
- What is being tested?
- a low FODMAP diet for 4 weeks
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 2 sitesUnited States
- Study dates
- 3 Aug 2020to 15 May 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
University of Michigan
Ann Arbor, Michigan, 48109
Beth Israel Deaconess Medical Center
Boston, Massachusetts, 02215
About this study
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
- Being tested
- a low FODMAP diet for 4 weeks
- Medical subject headings
- Irritable Bowel Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
a low FODMAP diet for 4 weeksOther
low FODMAP diet for 4 weeks
| Study group | Role | What they receive |
|---|---|---|
| Study patients with IBS-D | Experimental | Patients with diarrhea-predominant IBS who will undergo a low FODMAP diet for 4 weeks Receives: Other: a low FODMAP diet for 4 weeks |
What is being measured
The primary outcome is the main question the study is designed to answer.
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
Measured: 4 weeks
Secondary outcomes (6)
Changes in Epithelial Permeability - Tight Junction Gene Expression
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).
Measured: 4 weeks
Changes in Epithelial Permeability - Quantitative Tight Junction Immunostaining
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.
Measured: 4 weeks
Changes in Stool Microbiome - Alpha Diversity
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.
Measured: 4 weeks
Changes in Stool Microbiome - Beta Diversity
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 difference between groups, meaning the dissimilarity is similar both within and between groups
Measured: 4 weeks
Immunohistochemistry for Mast Cells
Number of mast cells in sample after immunohistochemistry were counted.
Measured: 4 weeks
Gastrointestinal Patient Reported Outcomes Measurement Information System (PROMIS)
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 discomfort.
PROMIS diarrhea asks how many days did you have loose stools, interference with activities, bothersomeness, and how often you experience urgency.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Sep 2020
- Study start3 Aug 2020
- Primary completion15 May 2024
- Study completion15 May 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Irritable Bowel SyndromeStudies of the same condition, open and under way.
- More trials run by University of MichiganThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 48 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Prashant Singh, University of Michigan
- Investigators
- Prashant Singh, Principal investigator, University of Michigan
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04542018
- Sponsor's protocol ID
- HUM00166423
- Other IDs
- K23DK129327
- Status last verified
- Jul 2025
- First submitted
- 1 Sep 2020
- Last updated
- 30 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
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.
PubMed 40749856
Study at a glance
From the registry record, last updated by the sponsor on 30 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Low FODMAP Diet on Colonic Epithelial Physiology in Diarrhea-predominant Irritable Bowel Syndrome
- ClinicalTrials.gov ID
- NCT04542018
- Acronym / sponsor ID
- HUM00166423
- Conditions
- Irritable Bowel Syndrome
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 48 participants (actual)
- Lead sponsor
- University of MichiganUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 3 Aug 2020 (actual)
- Primary completion
- 15 May 2024 (actual)
- Study completion
- 15 May 2024 (actual)
- First posted
- 9 Sep 2020 (actual)
- Results
- Posted 30 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Study patients with IBS-D | Experimental | Other: a low FODMAP diet for 4 weeksPatients with diarrhea-predominant IBS who will undergo a low FODMAP diet for 4 weeks |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| a low FODMAP diet for 4 weekslow FODMAP diet for 4 weeks | Other | Study patients with IBS-D |
Primary outcome
Lactulose Mannitol Excretion
Time frame: 4 weeks
Changes in cumulative excretion of lactulose and mannitol in timed urine collection before and after low FODMAP diet measured during 8-24h
6 secondary outcomes
Changes in Epithelial Permeability - Tight Junction Gene Expression
Time frame: 4 weeks
Changes in Epithelial Permeability - Quantitative Tight Junction Immunostaining
Time frame: 4 weeks
Changes in Stool Microbiome - Alpha Diversity
Time frame: 4 weeks
Changes in Stool Microbiome - Beta Diversity
Time frame: 4 weeks
Immunohistochemistry for Mast Cells
Time frame: 4 weeks
Gastrointestinal Patient Reported Outcomes Measurement Information System (PROMIS)
Time frame: 4 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 40749856Gao 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.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Prashant Singh principal investigator
University of Michigan
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing a low FODMAP diet for 4 weeks in people with Irritable Bowel Syndrome, run by University of Michigan at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 30 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Lactulose Mannitol Excretion (time frame: 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04542018, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jul 2025.