This research is studying whether changing an individual's diet may have an impact as a treatment or outcome for Irritable Bowel Syndrome (IBS). This research will show if diet might play a role in triggering changes that may cause IBS. This study is being done to learn if a low FODMAP (fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols) diet causes changes in the colon lining which mediates improvement in IBS symptoms.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
48
low FODMAP diet for 4 weeks
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
University of Michigan
Ann Arbor, Michigan, United States
Lactulose Mannitol Excretion
Changes in cumulative excretion of lactulose and mannitol in timed urine collection before and after low FODMAP diet measured during 8-24h
Time frame: 4 weeks
Changes in Epithelial Permeability - Tight Junction Gene Expression
Changes in tight junction (TJ) gene expression in colonic biopsies before and after low FODMAP diet Gene expression of Tight junction proteins were normalized to that of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH).
Time frame: 4 weeks
Changes in Epithelial Permeability - Quantitative Tight Junction Immunostaining
Changes in Quantitative tight junction immunostaining of tight junctions in colonic biopsies before and after low FODMAP diet Data is reported as ratio of TJ proteins to NA-K ATPase.
Time frame: 4 weeks
Changes in Stool Microbiome - Alpha Diversity
Changes in relative abundance of bacteria before and after low FODMAP diet. Alpha diversity was measured as number of Amplicon Sequence Variant (ASV) measured in the specimen.
Time frame: 4 weeks
Changes in Stool Microbiome - Beta Diversity
Changes in relative abundance of bacteria before and after low FODMAP diet. For the beta diversity, an analysis of similarities (ANOSIM)test based on Bray-Curtis distances is the best measure if the communities were different. The ANOSIM R statistic gives the scale of difference. ANOSIM R ranges from -1 to 1, where 1 means there is most interparticipant similarity within the group compared with between the different groups, and where -1 means there is least interparticipant similarity within the group compared with between the different groups. A value close to 0 indicates no significant difference between groups, meaning the dissimilarity is similar both within and between groups
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Time frame: 4 weeks
Immunohistochemistry for Mast Cells
Number of mast cells in sample after immunohistochemistry were counted.
Time frame: 4 weeks
Gastrointestinal Patient Reported Outcomes Measurement Information System (PROMIS)
PROMIS scales of Belly pain (5a) and diarrhea (6a) will be administered to assess the severity of belly pain and diarrhea in our patients. PROMIS Belly pain questionnaire and PROMIS diarrhea questionnaire have five and six questions, respectively, which assess symptom severity on a 5 point Likert scale. 50 indicates the general population mean with a standard deviation of 10. Higher T-scores on these questionnaires refer to more severe gastrointestinal symptoms. PROMIS belly pain asks how often did you have belly pain, severity of belly pain, interference with activities, bothersomeness and discomfort. PROMIS diarrhea asks how many days did you have loose stools, interference with activities, bothersomeness, and how often you experience urgency.
Time frame: 4 weeks