Effects of Blueberries on Symptoms and Underlying Mechanisms of Functional Gastrointestinal Disorders

Study Overview
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Brief Summary
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There is extensive pre-clinical evidence for potential health effects of blueberries. These are related, but not exclusively due to their high polyphenol content. This translational, clinical, randomized, cross-over, double-blind, placebo-controlled study will investigate the effects of blueberries in freeze-dried powder form on gastrointestinal and extra-gastrointestinal symptoms and function, as well as specific potential underlying mechanisms, in patients with the overlapping functional gastrointestinal disorders, irritable bowel syndrome and functional dyspepsia.

Official Title
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Effects of Blueberries on Symptoms and Underlying Mechanisms of Functional Gastrointestinal Disorders

Conditions
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Functional Gastrointestinal Disorders

Intervention / Treatment
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* Dietary Supplement: Blueberry
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fifty-five successive male or female patients with Functional Gastrointestinal Disorders FGID) enrolled from our Gastroenterology Group Practice (GGP) in Bern, Switzerland, classified as having either Irritable Bowel Syndrome (IBS), Functional Dyspepsia (FD) or both according to Rome 4 criteria (Drossman et al 2016; Schmulson et al. 2017) Age between 18 and 50 years Body mass index 18.5-29.9 kg/m2 European / Caucasian ethnicity Able to give informed consent in German as documented by signature Exclusion Criteria: Evidence of clinically significant disease, as assessed by usual clinical practice (history, blood and stool tests, imaging and endoscopy, as clinically required) and by investigator. Colonoscopy, antibiotics or probiotics within 2 weeks before or during the study. Planned dietary modifications (including polyphenol-rich fruit or vegetable smoothies, drinks or diets) or initiation of new treatments during the study period, besides the study interventions. Inability or contraindications to undergo the investigated intervention Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Blueberry<br>Freeze-dried pure blueberry powder | Dietary Supplement: Blueberry<br>* freeze-dried Northern highbush blueberry powder twice daily 15g = 60kcal<br>|
| Placebo Comparator: Placebo<br>Maltodextrin powder. | Dietary Supplement: Placebo<br>* matched powder maltodextrin twice daily = 60kcal<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Gastrointestinal Symptom Rating Scale (GSRS) | Validated scale of GI symptoms | before and after 6 weeks of each treatment arm | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in cognitive neurological function tests | Cambridge Cognition neurocognitive test battery (CANTAB) | before and after 6 weeks of each treatment arm | 
| Change in musculoskeletal symptoms | Validated Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) scores | before and after 6 weeks of each treatment arm | 
| Change in breath gas concentrations and symptoms scores during fructose breath testing | AUCs (areas under curve) of hydrogen, methane and symptom scores during fructose breath tests | before and after 6 weeks of each treatment | 
| Change in laboratory markers for advanced glycation end products, tight junction proteins | Validated biochemical markers of advanced glycation, tight junction protein quantification | before and after 6 weeks of each treatment |