GASTROINTESTINAL SYMPTOMS, HYDROGEN EXCRETION AND GASTROINTESTINAL CONDITIONS MEASURED WITH SMARTPILL® IN IRRITABLE BOWEL SYNDROME PATIENTS - MEAL STUDY ON LOW-FODMAP AND REGULAR RYE BREAD-MEALS

Background and objectives: Grains are often considered as triggers of irritable bowel syndrome (IBS) symptoms but less is known about effects of grain products with differing content of FODMAPs on gastrointestinal transit times, pH and intraluminal pressure in patients with IBS. In a previous study intraluminal pH was lower among IBS subjects than in healthy controls possibly demonstrating higher rate of colonic fermentation in IBS. Methods: Our aim was to evaluate if rye bread low in FODMAPs would cause less hydrogen excretion, lower intraluminal pressure, higher colonic pH and less IBS symptoms than regular rye bread. The study was conducted as a randomized double blind controlled cross-over meal study. Female IBS patients (n=7) ate study breads on 3 consecutive meals, i.e. for breakfast, lunch and dinner and were followed for 630 minutes. Intraluminal conditions were measured by SmartPill®, an indigestible motility capsule. Results: Postprandial hydrogen excretion, a marker of colonic fermentation, expressed as AUC(0-630 min) was [median (range)] 6300 (1785-10800) for low-FODMAP rye bread and 10 635 (4215-13080) for regular bread (p=0.028). The means of the VAS measurements of individual gastrointestinal symptoms during the follow-up (30 to 630 min) tended to be numerically lower after the low-FODMAP rye bread but did not show any statistically significant differences between the breads. Intraluminal pressure correlated significantly with total symptom score after regular rye bread (p=0.786, p=0.036) and nearly significantly after low-FODMAP bread consumption (p=0.75, p=0.052). We found no differences in pH, contractions or gastrointestinal transit times between the breads. Gastric emptying of SmartPill was slower than reported in previous studies. Conclusions: Our meal study demonstrated that low-FODMAP rye bread reduces colonic fermentation but no difference could be found in median values of IBS symptoms, pH, colonic pressure of gastrointestinal tract when compared to regular rye bread. Our observation on the correlation between increased intra-colonic pressure and symptom severity warrants further studies in IBS.