Not Yet RecruitingNot Applicable

IBS-Oriented CDED Versus Low FODMAP Diet for Irritable Bowel Syndrome

150 participantsStarted 2026-07-07

Plain-language summary

Background: Irritable Bowel Syndrome (IBS) affects approximately 4.1% of the global population and imposes a significant personal and healthcare burden. Recent evidence highlights the role of low-grade inflammation, impaired intestinal permeability and gut microbiota dysbiosis in the pathophysiology of non-constipated IBS (IBS with predominate diarrhea; IBS-D and mixed type IBS; IBS-M). Most patients report food-related symptom exacerbation, making dietary intervention a cornerstone of treatment. While the low-FODMAP diet (LFD) is widely used to reduce fermentable carbohydrates and alleviate symptoms, it may negatively affect microbial diversity and lacks anti-inflammatory effects. In contrast, the Crohn's Disease Exclusion Diet (CDED), developed for Crohn's disease, has demonstrated the ability to reduce intestinal inflammation, improve barrier function, and promote a favorable microbiota profile. These mechanisms may be relevant and beneficial in IBS, but have yet to be studied in this population. Objectives: To compare the efficacy of a modified CDED to the LFD for the treatment of non-constipated IBS symptoms, Hypothesis: A modified CDED will be at least as effective as the LFD in alleviating non-constipation IBS symptoms, stool consistency, quality of life, and psychological distress, while demonstrating superior effects on markers of low-grade inflammation, gut microbiota composition, and intestinal permeability. Methods: This is a single-center, open-label, randomized study to be conducted at the Gastroenterology Department of Sheba Medical Center. 136 adults diagnosed with Rome IV-defined IBS-D or IBS-M and an IBS Symptom Severity Score (IBS-SSS) ≥175 will be randomized 1:1 to receive either a modified CDED or the LFD for 6 weeks. Accounting for a 10% dropout rate, the total sample size will be 150. Following a 14-day screening period, eligible participants will undergo data collection at baseline, week 3 and week 6. Visit 1 (screening) will be conducted on-site; visits 2-4 will be remote. Participants will complete daily symptom diaries \[Bristol Stool Form Scale (BSFS) and GI Visual Analogue Scale (VAS)\], and weekly IBS-SSS. Validated questionnaires assessing psychological distress, somatization, extraintestinal symptoms, and quality of life will be administered at each time point. Stool samples will be collected at baseline, week 3, and week 6. Fecal calprotectin (FC) and α1-Antitrypsin (A1AT) will be analyzed as markers of intestinal inflammation and permeability. Microbiota analysis will be conducted using 16S rRNA gene sequencing, with evaluation of microbial diversity, taxonomic shifts, and associations with clinical and biological outcomes. Significance: This is the first study to evaluate the modified CDED as a dietary intervention for the treatment of IBS. It may offer a novel, inflammation-targeted alternative treatment for IBS.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Adults, men, and women (≥18 years) are diagnosed with IBS-D or IBS-M according to Rome IV criteria. * Moderate-to-severe symptoms (IBS-SSS score ≥175). * Stable use of any IBS-related medications for ≥6 weeks before study enrollment, except for antibiotics Exclusion Criteria: * Coexisting GI diseases \[e.g., Crohn's disease, ulcerative colitis, SIBO, celiac disease \[positive transglutaminase (TTG) serology\]. * Disease that could explain or influence symptoms or GI function, including diabetes, thyroid disease \[abnormal Thyroid-Stimulating Hormone (TSH)\], and bariatric surgery. * Recent intestinal resection. * Pregnancy or breastfeeding. * Known food allergies. * Current active eating disorder * Participants already following a restrictive diet, including diets that overlap with the interventions in this study, will be excluded to prevent confounding effects on gut microbiota composition and gastrointestinal symptoms, and to ensure consistent baseline conditions. However, individuals who have discontinued such diets at least two to four weeks prior to enrollment may be eligible, allowing for a sufficient dietary washout period to minimize residual effects on the gut microbiota. * Currently under obesity management medication treatment. * Vegans * Use of antibiotics within the 4 weeks prior to enrollment or during the study period. * Abnormal hemoglobin levels (for women\<11.5 gr/dl, for men\<13 gr/dl)29 * Baseline CRP≥5

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Proportion of participants achieving a clinically meaningful response (≥50-point reduction in IBS Symptom Severity Score [IBS-SSS])

Timeframe: Baseline and Week 6

Trial details

NCT IDNCT07707635

SponsorAriel University

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2028-07-30

Contact for this trial

Keren Hod, RD PhD

+972-53-2214380 kerenho@ariel.ac.il

View on ClinicalTrials.gov More Irritable Bowel Syndrome (IBS) trials