Efficacy and findings of a blinded randomized reintroduction phase for the low FODMAP diet in Irritable Bowel Syndrome.

BACKGROUND AND AIMS: The efficacy of a low fermentable oligo-, di-, monosaccharides and polyols (FODMAP) diet in Irritable Bowel Syndrome (IBS) is well established. After the elimination period, a reintroduction phase aims to identify triggers. We studied the impact of a blinded reintroduction using FODMAP-powders to objectively identify triggers and evaluated the effect on symptoms, quality of life (QoL), and psychosocial co-morbidities.

METHODS: Responders to a 6-week low-FODMAP diet, defined by a drop in IBS-symptom severity score (IBS-SSS) compared to baseline, entered a 9-week blinded randomized reintroduction phase with 6 FODMAP powders (fructans, fructose, galacto-oligosaccharides, lactose, mannitol, sorbitol) or control (glucose). A rise in IBS-SSS (≥50 points) defined a FODMAP-trigger. Patients completed daily symptom diaries and questionnaires for QoL and psychosocial co-morbidities.

RESULTS: In 117 recruited IBS patients, IBS-SSS improved significantly after the elimination period compared to baseline (150±116 vs 301±97, P < .0001, 80% responders). Symptom recurrence was triggered in 85% of the FODMAP powders, by an average of 2.5±2 FODMAPs/patient. The most prevalent triggers were fructans (56%) and mannitol (54%), followed by galacto-oligosaccharides, lactose, fructose, sorbitol, and glucose (respectively 35%, 28%, 27%, 23%, and 26%) with a significant increase in abdominal pain at day 1 for sorbitol/mannitol, day 2 for fructans/galacto-oligosaccharides and day 3 for lactose.

CONCLUSION: We confirmed the significant benefit of the low-FODMAP diet in tertiary care IBS. A blinded reintroduction revealed a personalized pattern of symptom recurrence, with fructans and mannitol as the most prevalent, and allows the most objective identification of individual FODMAP-triggers; Clinicaltrial.gov number: NCT04373304.