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

NCT07707635 | Not Yet Recruiting

• 3 other identifiers: 2495-25-SMC0009547202540302
• Study Type: interventional
• Target: 150
• Locations: 0 countries
• Sites: N/A

Brief 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.

Conditions

Irritable Bowel Syndrome (IBS)

Keywords

Crohn's Disease Exclusion Diet (CDED); Low FODMAP Diet; Diet Therapy; Gut Microbiota; Intestinal Permeability; Fecal Calprotectin; Alpha-1 Antitrypsin; IBS-D; IBS-M

Outcome Measures

Primary Outcomes (1)

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

  The primary efficacy outcome is the proportion of participants achieving a clinically meaningful response, defined as a reduction of at least 50 points from baseline in the IBS Symptom Severity Score (IBS-SSS) after 6 weeks of treatment. The IBS-SSS is a validated questionnaire ranging from 0 to 500, with higher scores indicating greater symptom severity.

  Baseline and Week 6

Secondary Outcomes (11)

• Proportion of participants achieving a ≥100-point reduction in IBS Symptom Severity Score (IBS-SSS)

  Baseline and Week 6

• Proportion of participants achieving a ≥50% reduction in IBS Symptom Severity Score (IBS-SSS)

  Baseline and Week 6

• Change from baseline in IBS Symptom Severity Score (IBS-SSS)

  Baseline, Week 3, and Week 6

• Change from baseline in gastrointestinal symptom severity (Visual Analog Scale)

  Baseline, Week 3, and Week 6

• Change in quality of life

  Baseline, Week 3, and Week 6

Study Arms (2)

Modified Crohn's Disease Exclusion Diet (CDED)

EXPERIMENTAL

Participants randomized to this arm will follow a modified Crohn's Disease Exclusion Diet (CDED) adapted for patients with irritable bowel syndrome. The intervention excludes the enteral formula used in the original CDED protocol and is delivered for 6 weeks with individualized dietary counseling.

Other: Modified Crohn's Disease Exclusion Diet (CDED)

Low FODMAP Diet

ACTIVE COMPARATOR

Participants randomized to this arm will follow a standard low FODMAP diet for 6 weeks with individualized dietary counseling.

Other: Low FODMAP Diet

Interventions

Modified Crohn's Disease Exclusion Diet (CDED) OTHER

Participants will follow a modified Crohn's Disease Exclusion Diet (CDED) adapted for patients with irritable bowel syndrome. The intervention excludes the enteral formula used in the original CDED protocol and is delivered for 6 weeks with individualized dietary counseling.

Modified Crohn's Disease Exclusion Diet (CDED)

Low FODMAP Diet OTHER

Participants will follow a standard low FODMAP diet for 6 weeks with individualized dietary counseling.

Low FODMAP Diet

Eligibility Criteria

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

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Ariel University: lead
• Sheba Medical Center: collaborator
• Ministry of Innovation, Science and Technology of Israel: collaborator

Related Links

• Study Recruitment Website

MeSH Terms

Conditions

Irritable Bowel Syndrome; alpha 1-Antitrypsin Deficiency

Interventions

FODMAP Diet

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases; Liver Diseases; Lung Diseases; Respiratory Tract Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Subcutaneous Emphysema; Emphysema; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Elimination Diets; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Keren Hod, RD PhD

  Ariel University

  STUDY CHAIR

Central Study Contacts

Keren Hod, RD PhD

CONTACT

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

Tal Engel, MD

CONTACT

+972-52-5752211; talengel@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will be randomized in a 1:1 ratio to receive either a modified Crohn's Disease Exclusion Diet (CDED) or a Low FODMAP Diet for 6 weeks. Both intervention groups will be followed concurrently throughout the study.

Study Record Dates

• First Submitted: July 5, 2026
• First Posted: July 16, 2026
• Study Start: July 7, 2026
• Primary Completion (Estimated): July 30, 2028
• Study Completion (Estimated): December 31, 2028
• Last Updated: July 16, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share