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Most patients suffering from the irritable bowel syndrome (IBS) report that ingestion of certain foods is a major trigger of symptoms, but the reason is unclear. Previous studies have shown that foods containing poorly absorbed carbohydrates (FODMAPs) are fermented by the bacteria in our bowels and these cause symptoms in some but not all patients. Gut bacteria are capable of producing various products, such as neuroimmune mediator histamine, that may be related to IBS symptoms. Our recent data suggest that consumption of FODMAPs promotes production of bacterial histamine.
The main objective of this study is to investigate bacterial production of histamine and its relationship to IBS symptoms. The study will involve 6 weeks on a low-FODMAP diet with three three-day interventions consisting of High- or Low-FODMAP drinks along with probiotics or placebo capsules. The patient's bacteria and metabolites will be analyzed at various time points.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Group A | Experimental | Participants in group A will undergo challenges in the order:
Challenges each last 5 days, but the FODMAP drinks and the L-Histidine capsules are only taken for the last three days. There is a 10 day washout period between challenges. |
|
| Group B | Experimental | Participants in group A will undergo challenges in the order:
Challenges each last 5 days, but the FODMAP drinks and the L-Histidine capsules are only taken for the last three days. There is a 10 day washout period between challenges. |
|
| Group C | Experimental | Participants in group A will undergo challenges in the order:
Challenges each last 5 days, but the FODMAP drinks and the L-Histidine capsules are only taken for the last three days. There is a 10 day washout period between challenges. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| L-Histidine | Dietary Supplement | 1 capsule (0.6g) twice daily |
|
| Measure | Description | Time Frame |
|---|---|---|
| Metabolites in stool, urine and blood | Metabolites will be measured by LC-MS and ELISA at baseline and before and after each intervention. | six weeks |
| Measure | Description | Time Frame |
|---|---|---|
| Expression of hdc gene by stool bacteria | Gram-positive and Gram-negative bacteria will be assessed by PCR using custom designed primers | six weeks |
| Stool microbiota composition | 16S rRNA Illumina sequencing of stool samples with culture-enriched sequencing. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Premysl Bercik, MD | McMaster University | Principal Investigator |
| Stephen Vanner, MD | Queens University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| McMaster University Medical Centre | Hamilton | Ontario | L8N 3Z5 | Canada | ||
| Kingston Health Sciences Centre |
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| ID | Term |
|---|---|
| D043183 | Irritable Bowel Syndrome |
| ID | Term |
|---|---|
| D003109 | Colonic Diseases, Functional |
| D003108 | Colonic Diseases |
| D007410 | Intestinal Diseases |
| D005767 | Gastrointestinal Diseases |
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| ID | Term |
|---|---|
| D006639 | Histidine |
| ID | Term |
|---|---|
| D000598 | Amino Acids, Cyclic |
| D000596 | Amino Acids |
| D000602 | Amino Acids, Peptides, and Proteins |
| D000601 | Amino Acids, Essential |
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|
| High-FODMAP beverage | Dietary Supplement | High-FODMAP beverage (10g of fermentable carbohydrates) consumed twice daily. |
|
| Low-FODMAP beverage | Dietary Supplement | Low-FODMAP beverage (10g glucose) consumed twice daily. |
|
| Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2. | Dietary Supplement | Total of 50 billion CFU/capsule taken twice daily. |
|
|
| Placebo | Other | Enteric coated capsule with no active ingredient, taken twice daily |
|
| six weeks |
| Worsening of IBS symptoms following High-FODMAP challenge | Increase by ≥50 points on IBS Symptom Severity Score (IBS-SSS). The score will be used as a dichotomous variable. The overall score ranges from 0 to 500, with higher scores indicating greater symptom severity. | six weeks |
| Changes in IBS symptoms | IBS-SSS continuous data. The overall score ranges from 0 to 500, with higher scores indicating greater symptom severity. | six weeks |
| Changes in general GI symptoms | Patient-Reported Outcomes Measurement Information System (PROMIS) for general GI symptoms. Four subscales will be used: Gas & Bloating, Diarrhea, Constipation, and Belly Pain. T-scores are calculated using the Scoring Service by Health Measures and range from 34.7 - 79.0 (Gas & Bloating), 39.9 - 75.2 (Diarrhea), 40.6 - 80.8 (Constipation), and 33.9 - 80.0 (Belly Pain). On this scale, 50 indicates the mean of the general population and a difference of 10 is a standard deviation. Higher scores indicate greater symptom severity. | six weeks |
| Levels of anxiety, depression and stress | Depression Anxiety Stress Scale (DASS-21) to assess psychiatric comorbidity and stress. The scale scores range from 0 - 42 with higher scores indicating worse outcomes. | six weeks |
| Changes in dietary intake | 5-day food diaries will be completed at 5 time points. FODMAP intake will be quantified using Monash University software and database | six weeks |
| Kingston |
| Ontario |
| K7L 2V7 |
| Canada |
| D004066 | Digestive System Diseases |