Breath test may predict which IBS patients benefit from Dairy-Free diet

NCT ID NCT04974593

Knowledge-focused Sponsor: Universitair Ziekenhuis Brussel Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study looks at whether a simple breath test can tell if people with moderate to severe irritable bowel syndrome (IBS) will feel better on a lactose-free diet. About 90 adults with IBS will take the breath test and then follow a lactose-free diet for 4 weeks. Researchers will track symptom changes and quality of life to see if the test results match who improves.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

About 90 people

The number the study aims to enrol. It can still change while the study runs.

Started

Oct 2021

Expected to finish

Jan 2028

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 75 years

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Fulfilling the ROME IV criteria for IBS; * Moderate symptom severity as defined by a IBS-SSS \> 175; * Consumption of lactose containing products. Exclusion Criteria: * Clinical suspicion of an organic disorder different from LI or IBS (patients can be included when this disorder had been excluded); * Known lactose intolerance or malabsorption; * Known inflammatory bowel disorder; * Known intestinal motility disorder; * Alcohol (defined as more than 14 U per week) or other substance abuse; * Active psychiatric disorder; * Known systemic or auto-immune disorder with implication for the GI system; * Prior abdominal surgery (with the exception of appendectomy); * Any prior diagnosis of cancer other than basocellular carcinoma; * Current chemotherapy; * History of gastro-enteritis in the past 8 weeks; * Intake of antibiotics, pre- or probiotics during the past 8 weeks; * Dietary supplements unless taken at a stable dose for more than 8 weeks; * Treatment with neuromodulators (one neuromodulator taken at a stable dose for more than 12 weeks is allowed); * Treatment with spasmolytic agents, opioids, loperamide, gelatin tannate or mucoprotect-ants during the past 8 weeks; * LFD or low FODMAP diet in the past

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Conditions

The condition(s) this trial relates to.

irritable bowel syndrome lactose intolerance

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Irritable bowel syndrome Lactose intolerant

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

1 site. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

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A doctor treating you

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Breath test may predict which IBS patients benefit from Dairy-Free diet

What the study statuses mean