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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
QUADRUPLE
Enrollment
30
1 capsule (0.6g) twice daily
High-FODMAP beverage (10g of fermentable carbohydrates) consumed twice daily.
Low-FODMAP beverage (10g glucose) consumed twice daily.
Total of 50 billion CFU/capsule taken twice daily.
Enteric coated capsule with no active ingredient, taken twice daily
McMaster University Medical Centre
Hamilton, Ontario, Canada
Kingston Health Sciences Centre
Kingston, Ontario, Canada
Metabolites in stool, urine and blood
Metabolites will be measured by LC-MS and ELISA at baseline and before and after each intervention.
Time frame: six weeks
Expression of hdc gene by stool bacteria
Gram-positive and Gram-negative bacteria will be assessed by PCR using custom designed primers
Time frame: six weeks
Stool microbiota composition
16S rRNA Illumina sequencing of stool samples with culture-enriched sequencing.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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
Time frame: six weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.