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

Study Overview
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Brief Summary
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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.

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

Conditions
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Irritable Bowel Syndrome

Intervention / Treatment
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* Other: a low FODMAP diet for 4 weeks


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 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. Exclusion criteria 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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional 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)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study patients with IBS-D<br>Patients with diarrhea-predominant IBS who will undergo a low FODMAP diet for 4 weeks | Other: a low FODMAP diet for 4 weeks<br>* low FODMAP diet for 4 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lactulose Mannitol excretion | Changes in cumulative excretion of lactulose and mannitol in timed urine collection before and after low FODMAP diet | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in epithelial permeability | Changes in tight junction gene expression, immunostaining of tight junctions in colonic biopsies before and after low FODMAP diet | 4 weeks | 
| Changes in stool microbiome | Changes in relative abundance of bacteria before and after low FODMAP diet | 4 weeks |