Published online Mar 21, 2018. doi: 10.3748/wjg.v24.i11.1259
Peer-review started: January 11, 2018
First decision: February 26, 2018
Revised: March 1, 2018
Accepted: March 3, 2018
Article in press: March 3, 2018
Published online: March 21, 2018
Processing time: 64 Days and 3.6 Hours
FODMAPs are rapidly fermentable carbohydrates shown to aggravate gastrointestinal symptoms in irritable bowel syndrome (IBS). A major challenge in the research of IBS is the lack of objective markers of disease activity. Excretion of hydrogen and methane and colonic fermentation markers are among the rare easily available and objective markers of gastrointestinal circumstances during the consumption of FODMAPs or other poorly absorbable carbohydrates. Grains are often considered as triggers of irritable bowel syndrome symptoms but less is known about the effects of grain products with differing content of FODMAPs on gastrointestinal transit times, pH and intraluminal pressure in patients with IBS.
SmartPill, a motility monitoring capsule, which measures intraluminal pH, transit time and pressure, and might thus offer the means to gather objective data on gastrointestinal conditions in IBS patients. A combination of SmartPill data and measurements of perceived symptoms may improve our understanding on the etiology of IBS symptoms when consuming grains high in FODMAPs.
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. Intraluminal conditions were measured by SmartPill®, an indigestible motility capsule.
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 10635 (4215-13080) ppm∙min for regular bread (P = 0.028). The means of the visual analogue scale measurements of individual gastrointestinal symptoms did not show any statistically significant differences between the breads. Intraluminal pressure correlated significantly with total symptom score after regular rye bread (ρ = 0.786, P = 0.036) and nearly significantly after low-FODMAP bread consumption (ρ = 0.75, P = 0.052). We found no differences in pH, contractions or transit times between the breads. Gastric emptying of SmartPill was slower than expected on the basis of majority of research literature.
Our meal study demonstrated that low-FODMAP rye bread reduces colonic fermentation but no difference was found in median values of 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.
Our finding on the correlation of intracolonic pressure and symptom severity suggests that IBS symptoms might be worsened by any reason that leads to increased colonic pressure in IBS. Consequently, any therapeutic attempts to reduce intraluminal pressure and contractions might continue to be important therapeutic targets in IBS. The study also implied that SmartPill might not be an optimal device to evaluate the gastrointestinal circumstances during meal studies among IBS patients lasting less than 24 h, due to device’s inability to measure effects of a singular food bolus in a timely manner. Observation and feeding periods longer than 38 h are recommended for future research utilizing SmartPill, especially among people with IBS.