The Role That Food and Bacteria Play in Generating Abdominal Pain

Inclusion Criteria: * Adults aged 18-70 with IBS (Rome IV (now V) criteria) * PROMIS belly pain score \>12 Exclusion Criteria: 1. Concurrent significant organic GI pathology (i.e. celiac, IBD, etc.) as some symptoms may be related to their disease and not IBS. 2. Concurrent systemic disease and/or laboratory abnormalities considered by investigators to be risky or that could interfere with data collection. 3. Major gastrointestinal surgery (e.g. Roux en y, bowel resection) as symptoms may be related to previous surgery rather than IBS. 4. Body mass index above 35 kg/m2 as it is unknown how mediators in the GI tract that may be involved in pain signaling in the gut are affected by obesity. 5. History of active cancer in the last 5 years, other than basal cell cancer as the treatment may have impacted the GI tract. 6. Pregnant or breastfeeding women. 7. Active or recent participation (\< 1 month) in a clinical study. 8. Use of antibiotics, probiotics, during, or one month prior to the study as may affect gut microbiota. 9. Use of new medications less than 4 weeks prior to the study as may alter gut microbiota and/or IBS symptoms. 10. Allergies to any of the ingredients used in the study. 11. Any immune-compromising conditions as may affect GI symptoms. 12. Currently being treated for eating disorder, schizophrenia, psychosis or other acute mental disorders as participating in a diet challenge study may have negative impact on these disorders.