The Effect of Dietary Intervention on Symptoms, Epigenetics, and Gut Microbiota in IBS

Study Overview
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Brief Summary
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The aim of the present study is to research whether subjects with irritable bowel syndrome (IBS) display epigenetic/genetic changes or altered microbiota compared to a non-IBS control group. Further, we will investigate if these parameters as well as subjective IBS symptoms are affected by a 4-week long dietary intervention within the IBS patient group.

Detailed Description
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The study will be performed on 140 subjects with verified IBS. Patients will be recruited from the clinic of Gastroenterology or Internal medicine as well as primary health care centers. At the start of the study patients will fill out protocols concerning Rom IV criteria (to validate that IBS criteria are filled) as well as IBS symptom rating scales. They will be examined by a physician/researcher who will complete protocols of clinical data. Blood and fecal samples will be collected. A control group of healthy, non-IBS individuals will go through the same procedure as described above. Study participants with IBS will thereafter be randomized to receive an alternative diet resembling the FODMAP (Fermentable, Oligo-, Di-, Mono-saccharides And Polyols) diet (n=130), or to continue with their regular diet (control group; n=20). After 4 weeks of dietary intervention, there will be a follow-up where blood and fecal samples are once again collected. At this point in time, participants will also fill in IBS symptom rating scales again. Samples from baseline and 4 weeks will be used for genetic/epigenetic (including genomic-wide association studies), gut microbiota and inflammatory parameter analyses. Statistics To study differences in the above-mentioned parameters between patients and controls as well as before and after dietary intervention, Mann-Whitney U-test and Wilcoxon test will be used, respectively.

Official Title
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The Effect of Dietary Intervention on Symptoms in Relation to Genetical Characteristics, Epigenetics, Gut Microbiota, and Autoantibodies in IBS Patients

Conditions
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IBS - Irritable Bowel Syndrome

Intervention / Treatment
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* Other: Dietary intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Verified IBS according to Rom IV criteria. Exclusion Criteria: Serious mental or somatic disease Abuse Inability to understand he Swedish language Already on a diet (e.g. vegan, FODMAP, gluten-free).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dietary intervention subject group<br>n=130. Participants on low FODMAP-similar diet during 4-week study period. | Other: Dietary intervention<br>* Elimination of certain products.<br>|
| No Intervention: Control group<br>n=20. Participants on traditional IBS diet during 4-week study period. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genetic variation of enzymes regulating absorption of disaccharides | Genetic expression of disaccharide-degradating enzymes will be measured at baseline and related to the response of study participants to dietary intervention. | measured at baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Irritable bowel syndrome-subjective severity scores (IBS-SSS) ratings | Changes from baseline in subjective symptoms according to the IBS-SSS. | 4 weeks | 
| Visual analog scale for irritable bowel syndrome (VAS-IBS) ratings | Changes from baseline in subjective symptoms according to the VAS-IBS. | 4 weeks | 
| Gut microbiota composition | Changes from baseline in fecal microbiota analysed by 16rs | 4 weeks | 
| Cytokines | Changes from baseline in cytokine plasma concentrations will be assessed by ELISA. | 4 weeks | 
| microRNA expression | Changes from baseline in microRNA expression will be assessed. | 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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IBS, Epigenetics, Dietary intervention, Gut Microbiota, Inflammation, Genetics