The Effect of Gluten in Patients With Irritable Bowel Syndrome and Healthy Volunteers

Study Purpose

Patients with Irritable Bowel Syndrome (IBS) often link their symptoms to foods. Interest in dietary management recently increased, including the use of a gluten-free diet. To investigate relation of gluten-free diet (GFD) and IBS, a randomized, double-blind, placebo-controlled cross-over trial will be carried out in adults (>18) and patients with IBS according to Rome IV criteria. The aim is to assess gluten-free versus gluten-containing diet in IBS patients and Healthy Volunteers.

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 18 Years - 85 Years
Gender All
More Inclusion & Exclusion Criteria

Inclusion Criteria:

- Adult patients with IBS according to Rome IV criteria

Exclusion Criteria:

- allergy or documented intolerance to food, - severe cardiovascular, hepatic, neurological or psychiatric disease - serious gastrointestinal disease: including celiac disease and inflammatory bowel diseases (IBD), - diabetes - bowel dysfunction related to previous surgery - pregnant or lactating women - usage of antibiotics within 4 weeks before inclusion - strict avoidance of foods

Trial Details

Trial ID:

This trial id was obtained from, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

Sahlgrenska University Hospital, Sweden
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

Magnus Simrén, MD, PhD
Principal Investigator Affiliation Sahlgrenska University Hospital, Sweden
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries Sweden

The disease, disorder, syndrome, illness, or injury that is being studied.

Irritable Bowel Syndrome
Additional Details

The study is a randomized, double-blind, placebo-controlled, cross-over trial. The aim is to assess the effects of gluten-free diet (GFD) compared to gluten-containing diet (GCD) in IBS patients and Healthy Volunteers on gastrointestinal symptoms, visceral sensitivity, bacterial fermentation, psychological factors and quality of life. The primary hypothesis is that GFD decreases gastrointestinal symptoms compared to GCD and that this change is accompanied with reduced visceral sensitivity and change in bacterial fermentation. The secondary hypothesis is that GFD positively influences psychological factors and quality of life. IBS patients (Rome IV) and Healthy Volunteers are challenged with gluten in this randomized, double-blind, placebo-controlled, cross-over study. They start with GFD or GCD and cross over to the other intervention (both for 14 days). In between there is a wash-out period of at least 14 days. The subjects will get gluten-free meals (lunch and dinner) and have to sprinkle powder over the meals, concealed in sachets with either gluten (vital gluten) or placebo (rice starch). The subjects will follow a strict GFD during the GFD and GCD periods. The subjects will eat and drink as before the study during the washout period. Primary outcomes are change in gastrointestinal symptoms, assessed by questionnaires, including IBS Severity Scoring System (IBS-SSS) and Gastrointestinal Symtom Rating Scale-IBS (GSRS-IBS). A 50-point reduction in IBS-SSS indicates clinical response. Bacterial fermentation (exhaled hydrogen and methane) and visceral sensitivity will be measured using the Lactulose-Nutrient Challenge Test. Secondary outcomes are change in psychological factors and quality of life assessed by questionnaires, including CSI, HADS, HSPS, IBSQOL, PHQ-15 and VSI.

Arms & Interventions


Experimental: Group A

Gluten-free diet with placebo powder vs Gluten-free diet with gluten powder

Experimental: Group B

Gluten-free diet with gluten powder vs Gluten-free diet with placebo powder


Other: - Gluten-free diet with gluten powder

The subjects will sprinkle gluten powder over their meals, twice a day. (14 g/day vital gluten: Real Foods, Edinburgh, United Kingdom). Plastic sachet marked with B (WePack, Derbyshire, United Kingdom). Free of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs).

Other: - Gluten-free diet with placebo powder

The subjects will sprinkle placebo powder over their meals, twice a day. (14 g/day rice starch: Doves Farm Foods Ltd., Berkshire, United Kingdom) Plastic sachets marked with A (WePack, Derbyshire, United Kingdom). Low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs).

Contact a Trial Team

If you are interested in learning more about this trial, find the trial site nearest to your location and contact the site coordinator via email or phone. We also strongly recommend that you consult with your healthcare provider about the trials that may interest you and refer to our terms of service below.

International Sites

Magnus Simrén, Gothenburg, Västra Götland, Sweden




Magnus Simrén

Gothenburg, Västra Götland, 40530

Site Contact

Magnus Simrén, MD, PhD


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