Prevalence of FODMAP Intolerance and Joint Hypermobility Syndrome in Functional Bowel Patients and Association With Microbiome, Dyssynergic Defecation and Dietary Intervention - a Prospective Cohort Study With Health-related Intervention

Functional gastrointestinal disorders (FGID) are common in the general population. Symptoms such as pain, nausea, bloating, diarrhea or constipation may occur. Irritable bowel syndrome (IBS) is the most common FGID with a prevalence in the range of 5-25%. Medical attention is sought by 20-75% of patients who meet diagnostic criteria for IBS at some time in their lives. Quality of life is often impaired in IBS patients. In previous studies a diet low in FODMAP was shown to reduce gastrointestinal symptoms in IBS patients.

But still it is unknown which FGID patients (e.g. patients with irritable bowel syndrome, functional dyspepsia (FD), functional abdominal pain/bloating) profit most from such a diet which involves costs, time and significant lifestyle alteration.

To test for food intolerances, standard hydrogen breath tests using fructose or lactose as challenge substance are still commonly used and do present a nutritional challenge, however the usefulness of information gained is questionable. Fructose intolerance is as prevalent in IBS as in healthy volunteers, in fact when tested with the usual doses of 25-50g, prevalence of fructose intolerance ranges between 53% and 73%. Testing (genetic) for hypolactasia, is often, even in the professional setting, misunderstood as lactose intolerance testing. Most patients, who do have hypolactasia, i.e. almost no activity of intestinal brush-border enzyme lactase, tolerate up to 12g of lactose per day, remain asymptomatic and therefore should not be considered lactose intolerant. In addition, one must realize, that the vast majority in the world is hypolactasic and hypolactasia, or rather lactase persistence, constitutes a norm variant.

Recently it was shown that a standardized liquid mixed nutrient meal including 25g lactulose, but not with 15g lactulose, allows differentiation of IBS patients from healthy controls. This test, incorporating FODMAP lactulose, that, unlike lactose and fructose, is indigestible in all humans in the small intestine, plus a caloric load, reflecting a regular meal and everyday life, has therefore the potential to be a useful marker of nutrient intolerance in patients with suspected functional bowel disease.

Additionally, associations between FGID and JH/JHS have been recognized in the past decade. JH/JHS constitutes a hereditary disorder of connective tissue in which patients often report non-musculoskeletal symptoms, among them gastrointestinal complaints. Previous studies in Europe and the U.S. have reported a JHS prevalence of 20% in the general population.