The Role of Fiber in the Prevention and Treatment of Fecal Incontinence

The purpose of this study is to determine the effect of fiber supplementation on the fecal metagenome and metabolome in relation to symptoms and anorectal physiology in post-menopausal women with irritable bowel syndrome with diarrhea suffering from liquid stool fecal incontinence (FI.)

This is an open-label, single-arm study at Massachusetts General Hospital that aims to recruit post-menopausal female patients with solid stool fecal incontinence. The investigators hope that subjects taking a daily fiber supplement will experience reduced episodes and symptoms of fecal incontinence, measured through quality of life questionnaires and daily stool and food diaries. Subjects will undergo 2 anorectal manometry procedures. Stool samples will also be collected for metabolomic and metagenomic analysis.

Eligibility Criteria:
Inclusion Criteria:

1. Female, post-menopausal
2. Age 50-90 years old
3. BMI \>18.5 and \<40 kg/m2
4. Rome IV criteria for liquid stool fecal incontinence occurring at least twice per month
5. At least one FI episode during the run-in period
6. Compliant with reporting during run-in (completion of two 3-day food diaries and two 7-day bowel diaries)
7. Submission of two stool samples during the run-in period
8. Ability to follow verbal and written instructions
9. Informed consent form signed by the subjects

Exclusion Criteria:

1. Less than two episodes per month of liquid stool fecal incontinence
2. Non-compliance with reporting during run-in
3. Patients reporting laxative, enema, and/or suppository usage during the run-in period
4. GI tract structural abnormality that would increase likelihood of obstruction
5. Dysphagia, swallowing disorder, or history of esophageal structural lesions
6. History of GI lumen surgery within 60 days prior to entry into the study
7. Neurological disorders, metabolic disorders, or other significant disease that would impair their ability to participate in the study
8. Inability to tolerate or contraindication to performance of anorectal manometry
9. Celiac disease, Crohn's disease, ulcerative colitis
10. Current anorectal fistula and/or abscess
11. Age \<50 or \>90
12. BMI of \<18.5 or ≥40 kg/m2
13. History of allergic reaction to psyllium
14. Previous trial of soluble fiber supplementation for fecal incontinence within the previous 30 days
15. History of sacral nerve stimulator or artificial anal sphincter placement
16. Administration of investigational products within 1 month prior to Screening Visit
17. Subjects anticipating surgical intervention during the study

19. History of intestinal stricture (e.g., Crohn's disease) 20. History of intestinal obstruction or subjects at high risk of intestinal obstruction including suspected small bowel adhesions 21. History of malabsorption 22. Any other clinically significant disease interfering with the assessments of psyllium, according to the Investigator (e.g., disease requiring corrective treatment, potentially leading to study discontinuation) 23. Any relevant biochemical abnormality interfering with the assessments of psyllium, according to the Investigator 24. Patients with metallic implants within a 30 cm radius of the TAMS electromagnetic coil 25. Currently on opioids 26. Patients with severe cardiac disease, chronic renal failure, or previous GI surgery EXCEPT cholecystectomy, appendectomy, Nissen fundoplication, and partial colectomy 27. Patients with neurological diseases and increased intracranial pressure 28. Patients with impaired cognizance 29. Previous pelvic surgery/radiation, radical hysterectomy 30. Patients with Ulcerative Colitis or Crohn's Disease 31. History of or current rectal prolapse 32. Previous history of anal fissure, anal surgery (abscess), congenital anorectal malformation, fistulae or inflamed hemorrhoids 33. Pregnant women 34. Use of antibiotics in previous 60 days