Overview

Dietary modifications are often recommended as first-line treatment for irritable bowel syndrome, with the FODMAP diet being the most effective intervention to improve global gastrointestinal symptoms. Due to the heterogeneity of symptoms, patients often seek complementary or alternative therapies. This randomized clinical trial aims to determine whether osteopathic care provides additional improvement in gastrointestinal symptoms compared to sham osteopathic care, when both are combined with a flexible FODMAP diet. The trial will also assess the safety and tolerability of osteopathic care.

The main questions it aims to answer are:

Does osteopathic care reduce IBS symptom severity more than sham osteopathic care?

Does osteopathic care improve pain, quality of life, anxiety, fatigue, work productivity, and gut microbiota compared to sham osteopathic care?

Do participants adhere to the flexible FODMAP diet and osteopathic care, and are the effects of osteopathic care maintained at 3- and 6-months post-intervention?

Can pretreatment factors, such as sociodemographic characteristics, IBS severity, predominant symptoms, psychological state, or gut microbiota composition, predict response to osteopathic care?

What adverse effects occur with osteopathic care compared to sham care?

Participants will:

Visit the osteopathy clinic to receive four sessions of real or sham osteopathic care

Complete online assessments before and after the intervention, and at 3- and 6-months post-intervention

Provide stool samples before and after the four osteopathic or sham sessions

Keep a three-day food diary and a ten-day stool diary before and after the intervention, and at 3- and 6-months post-intervention

Eligibility

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.