Impact of Dietary Fiber Supplementation on Colonic Microbiome

PRIMARY OBJECTIVE: I. To identify how diet, specifically fiber supplementation, alters the microbiome of the colonic mucosa. OUTLINE: Patients receive dietary fiber orally (PO) once daily (QD) for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and at follow up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up.