EFFECT OF A DİETİTİAN-SUPERVİSED LOW-FODMAP DİET VERSUS STANDARD WRİTTEN ADVİCE ON GASTROİNTESTİNAL SYMPTOMS AND INFLAMMATORY BİOMARKERS İN IRRİTABLE BOWEL SYNDROME: A RANDOMİZED CONTROLLED TRİAL

NCT07619573 | Completed DMC

• 1 other identifier: 2015-KAEK-80-23-49/SKLOWFODMAP
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 2

Brief Summary

Background: Irritable Bowel Syndrome (IBS) is the most prevalent functional gastrointestinal (GI) pathology among GI disorders. Various dietary interventions, particularly the low-FODMAP diet, are employed to alleviate IBS symptoms. Study Population \& Design: This study will include 78 adult patients, aged 18-65, diagnosed with IBS according to Rome IV criteria at the Biruni University Faculty of Medicine Hospital Gastroenterology Outpatient Clinic. Participants will be divided into two parallel groups: Group 1 (n=39): Will receive dietary intervention solely through physician follow-up (provided with a standard hospital brochure listing prohibited foods). Group 2 (n=39): Will receive structured, personalized dietary intervention through individualized nutritional counseling by a dietitian. Duration: The low-FODMAP diet intervention for both groups will last for 8 weeks. Outcome Measures: At baseline (week 0) and at the conclusion of the study (week 8), the following assessments will be conducted: Clinical Scores: IBS Symptom Severity Score (IBS-SSS) and the 15-item Gastrointestinal Symptom Rating Scale (GSRS). Biomarkers: Hs-CRP and fecal calprotectin levels analyzed from blood and stool samples. Objective: The primary objective is to determine the impact of individualized nutritional counseling on GI symptoms and inflammatory biomarkers (hs-CRP, fecal calprotectin) during a low-FODMAP diet. Secondary objectives include evaluating the significance of the dietitian's role and observing how lifestyle factors (sleep and physical activity) influence symptom outcomes alongside nutritional therapy.

Conditions

Irritable Bowel Syndrome (IBS)

Keywords

Irritable Bowel Syndrome (IBS); low-FODMAP diet; gastrointestinal symptoms; dietitian

Outcome Measures

Primary Outcomes (4)

• IBS-SSS

  Irritable Bowel Syndrome Symptom Severity Score (IBS-SSS). The IBS-SSS consists of 5 questions, each scored from 0 to 100, with a maximum possible total score of 500. It determines the severity of abdominal pain, abdominal pain frequency, abdominal bloating severity, satisfaction with bowel habits, and the impact of the disease on quality of life. Total scores are classified as follows: 75-174 points = mild IBS, 175-299 points = moderate IBS, and greater than or equal to 300 points = severe IBS. Higher scores indicate more severe IBS symptoms.

  From enrollment to the end of treatment at 8 weeks

• GSRS

  Gastrointestinal Symptom Rating Scale (GSRS). The GSRS is a 15-item questionnaire that uses a 5-point Likert scale to assess the severity of gastrointestinal symptoms across 5 subscales: abdominal pain, reflux, diarrhoea, indigestion, and constipation. Scores are aggregated to determine symptom severity, where higher scores represent a higher severity of gastrointestinal symptoms.

  From enrollment to the end of treatment at 8 weeks

• Fecal Calprotectin

  Fecal calprotectin levels will be analyzed from stool samples collected from participants to evaluate gastrointestinal inflammation.

  From enrollment to the end of treatment at 8 weeks

• Hs-CRP

  High-Sensitivity C-Reactive Protein (hs-CRP). Hs-CRP levels will be analyzed from blood samples collected from individuals to monitor systemic biochemical findings of inflammation.

  From enrollment to the end of treatment at 8 weeks

Secondary Outcomes (5)

• Anthropometric measurement data

  From enrollment to the end of treatment at 8 weeks

• IPAQ-SF

  From enrollment to the end of treatment at 8 weeks

• Epworth Sleepiness Scale (ESS)

  From enrollment to the end of treatment at 8 weeks

• Data Collection Form

  At the beginning of the study

• Daily Total FODMAP Intake

  From enrollment to the end of treatment at 8 weeks

Study Arms (2)

Dietitian group

EXPERIMENTAL

A dietitian planned the low FODMAP diet for the first group (n=31) through individual dietary counselling.

Behavioral: Low-FODMAP Diet Intervention

Doctor group

ACTIVE COMPARATOR

The second group (n=19) was given a brochure on the low FODMAP diet, as is routine in the hospital, listing foods prohibited by the gastroenterologist.

Behavioral: Low-FODMAP Diet Intervention

Interventions

Low-FODMAP Diet Intervention BEHAVIORAL

This intervention consists of an 8-week low-FODMAP dietary regimen aimed at restricting the intake of short-chain carbohydrates, including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. The intervention is administered through two distinct protocols to compare delivery methods: one group receives standard hospital care consisting of a brief physician follow-up accompanied by a standard educational brochure listing prohibited foods, while the other group receives structured, individualized nutritional counseling and personalized meal planning led by a professional dietitian.

Dietitian group; Doctor group

Eligibility Criteria

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

You may qualify if:

• Adults aged 18-65 years.
• Diagnosed with IBS according to the Rome IV criteria.

You may not qualify if:

• Use of antibiotics, NSAIDs, oral contraceptives, or hormone therapy during the study.
• Pregnancy or breastfeeding.
• Diagnosis of celiac disease

Sponsors & Collaborators

• Biruni University: lead

Study Sites (2)

Biruni University Faculty of Medicine Hospital

Istanbul, Istanbul, Turkey (Türkiye)

Location

Biruni University

Istanbul, Istanbul, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Irritable Bowel Syndrome

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases

Study Officials

• Sevde KAHRAMAN, Asst. Prof.

  Biruni University

  STUDY CHAIR

• Zeynep Çavdar, Master's student and dietitan

  Biruni University

  STUDY DIRECTOR

• Koray Koçhan, Specialist of Gastroenterology

  Department of Gastroenterology, Biruni University Faculty of Medicine Hospital

  PRINCIPAL INVESTIGATOR

• Huri Demirci, PhD, Associate Professor

  Biruni University

  PRINCIPAL INVESTIGATOR

• Fatma Çelik, PhD, Professor

  Biruni University

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Asst. Prof.

Model Details: The patients were randomly assigned to two groups: One group (n=31) followed a low FODMAP diet under the guidance of a dietitian, while the other group (n=19) followed the diet based on a brochure provided by a doctor.

Study Record Dates

• First Submitted: May 26, 2026
• First Posted: June 2, 2026
• Study Start: April 1, 2025
• Primary Completion: October 1, 2025
• Study Completion: October 30, 2025
• Last Updated: June 2, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

TU (2)