The Effect of Diet on Microbial Profile and Disease Outcomes in Patients With Inflammatory Bowel Diseases

Study Overview
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Brief Summary
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This clinical study is designed to evaluate the effect of two dietary patterns, Mediterranean diet and the specific carbohydrate diet on clinical, inflammatory and microbial parameters in patients after pouch surgery and to assess the effect of a personal tailored diet, based on microbial profile, on disease outcomes and generate a predictive model for future interventions.

Detailed Description
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Increasing evidence exist regarding the role of diet in the pathogenesis of inflammatory bowel diseases. One possible mechanism for the effect of diet on intestinal inflammation is modification of the gut microbial composition. However, the relationship between diet, the microbiome and intestinal inflammation is still vague. The investigators plan to perform a crossover clinical trial. Seventy ulcerative colitis patients post restorative proctocolectomy (pouch) will be randomly allocated into two short-term (one week) dietary interventions, the Mediterranean diet and the specific carbohydrate diet, to assess which diet has the required influence (i.e. increased diversity, decrease in specific pathobionts and increase in anti-inflammatory taxa) on the gut microbiome of each participant. Based on this assessment, each participant will be treated by a personally-tailored diet for up to one year, during which microbial composition, clinical parameters, and quality of life will be assessed.

Official Title
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The Effect of the Mediterranean Diet and the Specific Carbohydrate Diet on Microbial Profile and Disease Outcomes in Patients With Inflammatory Bowel Diseases

Conditions
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Inflammatory Bowel Diseases, Crohn's Disease, Dietary Modification

Intervention / Treatment
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* Behavioral: Mediterranean diet
* Behavioral: Specific Carbohydrate Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18-75; Able and willing to sign an informed consent; Underwent pouch surgery because of refractory UC or Familial Adenomatous Polyposis (FAP) and have a functioning pouch. Exclusion Criteria: Patients with ileostomy, stricturing disease, use of antibiotics in the month prior to inclusion, significant comorbidity that precludes the patient from participating according to the physicians' judgment, non-Hebrew readers, pregnant and lactating women.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A<br>Patients will be allocated to 7 days of Mediterranean diet and then will cross over to 7 days of specific carbohydrate diet | Behavioral: Mediterranean diet<br>* The Mediterranean diet is rich in complex carbohydrates and fibers and low in animal proteins and fats.<br>Behavioral: Specific Carbohydrate Diet<br>* The specific carbohydrate diet is a dietary program popular among patients with IBD. The diet allows carbohydrate foods consisting of mono-saccharides only, and excludes di-saccharides and most polysaccharides.<br>|
| Experimental: Group B<br>Patients will be allocated to 7 days of specific carbohydrate diet and then will cross over to 7 days of Mediterranean diet | Behavioral: Mediterranean diet<br>* The Mediterranean diet is rich in complex carbohydrates and fibers and low in animal proteins and fats.<br>Behavioral: Specific Carbohydrate Diet<br>* The specific carbohydrate diet is a dietary program popular among patients with IBD. The diet allows carbohydrate foods consisting of mono-saccharides only, and excludes di-saccharides and most polysaccharides.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Microbial diversity | Shannon α-diversity index | 7 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical score | Pouchitis Disease Activity Index (PDAI) | 7 days | 
| C-reactive protein (CRP) | Inflammatory marker | 7 days | 
| fecal calprotectin | Inflammatory marker | 7 days | 
| Quality of life | Inflammatory bowel diseases questionnaire (IBDQ) | 7 days | 
| Microbial composition | Change in the abundance of microbial taxa | 7 days |