Efficacy of a Low FODMAP Diet in IBS Children and Impact on Urinary and Faecal Metabolome

February 4, 2026 updated by: Ruggiero Francavilla, University of Bari

Efficacy of a Low FODMAP Diet in IBS Children and Impact on Microbiota, Urinary and Faecal Metabolome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain associated with defecation, or changes in stool frequency or stool form .

The low FODMAPs diet (LFD) is a relatively new approach in the management of IBS and focuses on limiting intake of poorly absorbed carbohydrates.

FODMAPs are highly fermentable but poorly absorbed short-chain carbohydrates and polyols contained in a wide variety of foods. FODMAPs include oligosaccharides (fructans, fructo-oligosaccharides = FOS and galacto-oligosaccharides = GOS), disaccharides (lactose), monosaccharides (fructose), and polyols (sorbitol, mannitol, maltitol, xylitol, polydextrose, and isomalt).

Many studies and meta-analysis in adults have shown that a low FODMAPs diet is effective in reducing IBS symptoms, particularly bloating and abdominal pain. On the other hand, evidences in children are scarce.

Previous studies in adults have demonstrated differences in urine metabolites between IBS patients receiving LFD compared to a high FODMAP diet (HFD), providing interesting hypotheses for pathophysiological mechanisms in IBS.

Aim of this study is to evaluate the efficacy of a LFD on gastrointestinal symptoms in children with IBS. Moreover, the investigators will assess the impact of LFD vs a diet with a standard content of FODMAPs (SFD) on the fecal and urinary metabolomic profile of pediatric IBS patients.

This is a single center, prospective, single blind low versus standard FODMAPs diet trial with crossover performed at Pediatric Gastroenterology Unit at the University of Bari.

The trial includes four phases (run-in, low FODMAP diet, wash out and standard FODMAP diet). The run-in phase (weeks 1-2) aim to assess basal symptoms while on habitual diet and only symptomatic children (VAS>3) will progress to the dietetic intervention trial.

Then patients will be randomized to low or standard FODMAP diet for 14 days; then, children from both arms start the wash-out period of two weeks and subsequently start the final 2-week period on standard or low FODMAP diet.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Single center, prospective, single blind low versus standard FODMAPs diet trial with crossover performed at Pediatric Gastroenterology Unit at the University of Bari Metabolomic analysis will be performed at Department of Soil, Plant and Food Science, University of Bari Aldo Moro.

The study will include all consecutive patients diagnosed with IBS according to the Rome IV criteria at Giovanni XXII Children's Hospital of Bari. The Giovanni XXII Children's Hospital of Bari is the tertiary referral center for the diagnosis and follow-up of gastrointestinal disorders in our region, covering an estimated population of 1400000 children, (National Institute of Statistics-https://www.istat.it accessed on 1 January 2023) with more than 10000 children followed up in the gastrointestinal clinic.

The trial includes four phases (run-in, low FODMAP diet, wash out and standard FODMAP diet). The run-in phase (weeks 1-2) aim to assess basal symptoms while on habitual diet and only symptomatic children (VAS>3) will progress to the dietetic intervention trial.

Then patients will be randomized to low or standard FODMAP diet for 14 days; then, children from both arms start the wash-out period of two weeks and subsequently start the final 2-week period on standard or low FODMAP diet. The order of the dietetic regimens is established according a computer-generated randomization list.

Fecal and urinary samples for analyzing metabolome will be collected before interventions and at the end of each dietetic regimen.

The study adheres to the Declaration of Helsinki, was approved by the institutional ethical committee. All patients gave full written informed consent.

Dietetic intervention An experienced dietician will design two different dietetic regimens (SFD and LFD), as a tailored personalized menu of 2 weeks duration, with manual calculation of nutrients and kilocalories according child age and weight. At enrollment the dietician will explain the diets in detail to the families who will be not aware of the content of FODMAP (low vs. standard). Parents will be only advised that the purpose of the study is to "Assess whether changing the amount of certain foods in the diet could affects symptoms of IBS" and the concept of FODMAPs wont be never mentioned during the study. Both menus will be normocaloric and balanced in macro- and micronutrients in relation to the age of the patient under study, according to the main principles of the Mediterranean diet. All menus comprise five meals during the day: breakfast, snack, lunch, snack and dinner. Food options present in the menus will be agree between the dietician, parents and children.

The food intake will be recorded on a diary and the same dietician, during follow-up visits checked dietary compliance. A proper dietary adherence was defined if percentage of amount of food left was less than 10% and number of times non-compliant per week was less than 2.

Study Type

Interventional

Enrollment (Actual)

70

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Italy
    • Ba
      • Bari, Ba, Italy, 70126
        • Pediatric Department "B Trambusti" Ospedale Giovanni XXIII Via Amendola 270

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

a) age between 4 and 18 years; b) diagnosis of IBS according to Rome IV criteria; c) absence of other organic diseases; d) feeding via the oral route; e) ability to read and comprehend any employed questionnaires/scales; f) signed informed consent;

Exclusion Criteria:

a) organic disease b)some other FGID (not IBS) or lactose intolerance c) having already followed an exclusion diet d)in case of pregnancy e)eating disorders f) prior surgery of the gastrointestinal tract g) neurodevelopmental disabilities

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: LOW FODMAP-wash out- STANDARD FODMAPs
Arm starting with low fodmap diet
Other: LOW FODMAPs Diet
patients will be randomized to low or standard FODMAP diet for 14 days; then, children from both arms started the wash-out period of two weeks and subsequently started the final 2-week period on standard or low FODMAP diet. The LFD will have a FODMAP content expressed in grams 0.15 g/kg/d FODMAPs (maximum 10 g/day) while the SFD will contain 0.7 g/kg/d FODMAPs (maximum 60 g/day).
Other Names:
  • STANDARD FODMAPs Diet
Active Comparator: STANDARD FODMAPs-wash out-LOW FODMAP
Arm starting with standard fodmap diet
Other: LOW FODMAPs Diet
patients will be randomized to low or standard FODMAP diet for 14 days; then, children from both arms started the wash-out period of two weeks and subsequently started the final 2-week period on standard or low FODMAP diet. The LFD will have a FODMAP content expressed in grams 0.15 g/kg/d FODMAPs (maximum 10 g/day) while the SFD will contain 0.7 g/kg/d FODMAPs (maximum 60 g/day).
Other Names:
  • STANDARD FODMAPs Diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visual Analogue Scale
Time Frame: from running in and during all the dietetic treatment
0-10
from running in and during all the dietetic treatment
Irritable bowel Syndrome-Severity score
Time Frame: 15 days
Is a five-item questionnaire measuring frequency and intensity of abdominal pain, the severity of abdominal distension, dissatisfaction with bowel habits, and the interference of IBS with daily life, scoring from 0 to 500. Cut-off of to evaluate the severity of IBS: < 175 for mild IBS, 175-300 for moderate IBS, and > 300 for severe IBS
15 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Fecal and urinary Metabolome
Time Frame: 14 days
SCFA and VOCs
14 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Bari

Investigators

  • Principal Investigator: Ruggiero Francavilla, Prof, Interdisciplinary department of Medicine Pediatric section. University of Bari Aldo Moro

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2023

Primary Completion (Actual)

December 31, 2024

Study Completion (Actual)

December 31, 2024

Study Registration Dates

First Submitted

April 24, 2023

First Submitted That Met QC Criteria

September 27, 2024

First Posted (Actual)

October 1, 2024

Study Record Updates

Last Update Posted (Actual)

February 9, 2026

Last Update Submitted That Met QC Criteria

February 4, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IBS-FODMAP

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Study Protocol and CSR will be available on request via email (fernandacristofori@gmail.com)

IPD Sharing Time Frame

Available on request

IPD Sharing Access Criteria

Request via email at fernandacristofori@gmail.com

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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