OptiMized REsistaNt Starch in Inflammatory Bowel Disease: The MEND Trial

Inclusion Criteria: * Capable of giving informed consent, or if appropriate, have an acceptable representative capable of giving consent on the participant's behalf. * Enrolled in the main parent study. * Existing Crohn's disease or ulcerative colitis diagnosis. * In clinical remission or with mild disease (wPCDAI of 0-39.5 for CD; PUCAI of 0-30 for UC) with no changes in standard of care treatment for the previous month and without anticipated changes for the next month. * Ability and willingness to comply with study procedures (e.g. stool collections) for the entire length of the study. * Willing to provide consent/assent for the collection of stool samples. Exclusion Criteria: * Allergy to resistant starch or excipients. * Co-existing diagnosis with diabetes mellitus. * Treatment with another investigational drug or intervention throughout the study. * Current drug or alcohol dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements. * Inability or unwillingness of an individual or legal guardian to give written informed consent. * Concomitant chronic disease requiring medications. * Requirement for antibiotic therapy \>2 weeks duration. * Participant's microbiota does not respond to any of the resistant starch from the assembled panel as measured through the RapidAIM evaluation following the initial stool sample collection. * Patients with previous intestinal surgery.