Evaluating the Added Benefit of Osteopathic Care to a Flexi-FODMAP Diet in Fibromyalgia Patients With Irritable Bowel Syndrome

Inclusion Criteria: This study includes participants who meet the following criteria: 1. are over 18 years old; 2. have a diagnosis of IBS by a medical doctor according to the Rome IV criteria and have an IBS-SSS score of ≥175 (indicating moderate to severe IBS symptoms); 3. have a medical diagnosis of fibromyalgia or meet the 2016 American College of Rheumatology criteria, characterized by chronic (≥3 months) widespread pain(i.e., a Widespread Pain Index(WPI) score of ≥7 with a Symptom Severity Score of ≥5, or a WPI score of 4-6 with a Symptom Severity Score ≥9 on the Widespread Pain Index). Participants will be allowed to use probiotic products and follow a lactose-reduced diet, as long as they kept their usual intake throughout the study, unless a further reduction in lactose was recommended for those assigned to diet therapy. IBS medications, including antidepressants, will be allowed if used consistently at a stable dose for at least 2-3month prior to inclusion. Additionally, participants will need to be willing to adjust their current dietary habits in order to take part in the study. Exclusion Criteria: This study excludes participants who meet any of the following criteria: 1. have other gastrointestinal disorders (e.g., inflammatory bowel disease, celiac disease) that could explain the current symptoms; 2. have diseases affecting gastrointestinal function, including a history of bariatric surgery; 3. have allergies or food hypersensitivity (other than lactose intolerance); 4. have any major dietary restrictions or food allergies; 5. are pregnant or planning pregnancy during the trial (within the next seven months); 6. have a BMI ≤18 kg/m²; or 7) have received osteopathic care for IBS and/or are already following the FODMAP dietary intervention.