Clinical trial NCT04543474: Treatment Efficacy of Low FODMAP Versus Low Lactose Diet in IBS Patients
Official title: Treatment Efficacy of a Low FODMAP Diet Compared to a Low Lactose Diet in IBS Patients: a Randomized, Cross-over Designed Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: IBS - Irritable Bowel Syndrome
Lead sponsor: Cantonal Hospital of St. Gallen
Sponsor class: OTHER
First posted: 2020-09-10
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: A low FODMAP diet (LFD) has become a standard treatment in irritable bowel syndrome (IBS) patients. Compliant adherence to a LFD is challenging. The investigator looked at the effect of a LFD compared to a less restrictive low lactose diet (LLD) in a randomized cross-over trial with IBS patients.

Detailed description: Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder. It affects 10 - 20% of the adult population. Pharmaceutical therapy as bulking agents, anticholinergics, antispasmodics, and antidiarrheals are mostly unsatisfactory and many gastroenterologists recommend therefore dietary management. Most patients note that various foods elicit abdominal symptoms and therefore restrict their diet .

The low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet has currently the greatest evidence for efficacy in IBS. The rationale behind the LFD is the exclusion of poorly absorbed short-chain carbohydrates which would create an osmotic load, drag fluid into the small intestine and would be fermented by the colonic microbiome, both leading to abdominal distention and increased luminal influx. FODMAPs do not cause symptoms in healthy adults as they neither show these abnormalities in gut physiology nor suffer from visceral hypersensitivity .

It is not known however whether change in symptoms is induced by a reduction in all FODMAPs or simply a single component as for example lactose. If there is a lactase deficiency, as it is the case in 2-20% of Central- / Northern Europeans, lactose cannot be hydrolysed and causes the above mentioned symptoms. Many IBS patients avoid lactose, even though only few have a lactase deficiency. Lactose intolerance but not lactase deficiency is more frequent in patients with IBS. The investigator wanted to examine if the demanding LFD is more effective than elimination of lactose alone.

Our study, comparing in detail the effects of low FODMAP versus low lactose diet in IBS patients is a novelty, analysing a clinically highly relevant topic.

Eligibility criteria: Inclusion Criteria:

* functional bowel symptoms as defined by the Rome IV criteria
* subjective lactose intolerance

Exclusion Criteria:

* pharmacologic agents to alter symptoms (laxatives, antidiarrheal agents)
* smoking
* antibiotic therapy within the last 4 weeks
* gastrointestinal diseases (Celiac disease was excluded by negative serologic testing while on a gluten containing diet
* any type of food allergy

Primary outcomes:
measure: Change from gastrointestinal symptoms in Irritable Bowel Syndrome (IBS symptom severity score) from Baseline to "post intervention diet".
timeFrame: The IBS SSS was assessed at the end of the run in period and at the end of the intervention diets (low lactose and low FODMAP diet) at day 14, 35 and 77.
Secondary outcomes:
measure: IBS symptom severity subscore "abdominal pain severity"
timeFrame: IBS subscores were assesses at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77.
measure: IBS- symptom severity subscore "abdominal pain frequency"
timeFrame: IBS subscores were assesses at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77.
measure: IBS- symptom severity subscore "abdominal distension"
timeFrame: IBS subscores were assesses at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77.
measure: IBS symptom severity subscore "satisfaction with stool habits"
timeFrame: IBS subscores were assesses at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77.
measure: IBS symptom severity subscore "interference of IBS with daily life"
timeFrame: IBS subscores were assesses at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77.
measure: IBS symptom severity score
timeFrame: IBS SSS (total) was assessed at the end of the run-in (day 14), and wash-out phase (day 56).
measure: Stool frequency
timeFrame: Stool frequency was assessed daily throughout the study (day 1-77).
measure: Stool consistency
timeFrame: Stool consistency was assessed daily throughout the study (day 1-77).
measure: Body weight
timeFrame: Body weight was assesses at the beginning of the study (day 1) and at the end of each trial phase (run-in, first intervention diet, wash-out, second intervention diet) at day 14, 35, 56 and 77).
Other outcomes:
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