Irritable Bowel Syndrome and Control Volunteers: Diet Challenge

Inclusion Criteria: * Age 18-75 * Individuals with irritable bowel syndrome (IBS) * Healthy volunteers (healthy controls) with no prior history of gastrointestinal (GI) disease or symptoms * No dietary restrictions other than vegetarian Exclusion Criteria: * Inflammatory bowel disease, celiac disease, or certain types of abdominal cancer, as well as those with thyroid or liver issues * Abdominal surgery or abdominal radiation within 6 months of study participation, with an exception for C-section or gallbladder removal * Use of any prescription, over the counter, or herbal medications known to affect gastrointestinal function or study interpretation, such as opioids, inflammatory drugs or certain antidepressants, within 6 months prior to study participation for healthy volunteers, or within 2 days of study participation for participants with IBS. * An exception will be permitted for limited use of stable low doses of antidepressants for individuals who have been taking them for a period greater than one month. * Rescue medication such as Bisacodyl (dulcolax) to relieve severe constipation and allow for stool collection will be permitted when needed. * Use of Ozempic and Ozempic-type medications * Pregnant or breastfeeding women * Antibiotic use within 3 months of study participation * Use of prebiotics or probiotics within the 2 weeks before the study initiation * Regular tobacco use within the past 6 months