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
To compare the effects of regular vs low-FODMAP rye bread on irritable bowel syndrome (IBS) symptoms and to study gastrointestinal conditions with SmartPill®.
Our aim was to evaluate if rye bread low in FODMAPs would cause reduced hydrogen excretion, lower intraluminal pressure, higher colonic pH, different transit times, and fewer IBS symptoms than regular rye bread. The study was a randomized, double-blind, controlled cross-over meal study. Female IBS patients (n = 7) ate study breads at three consecutive meals during one day. The diet was similar for both study periods except for the FODMAP content of the bread consumed during the study day. Intraluminal pH, transit time, and pressure were measured by SmartPill, an indigestible motility capsule.
Hydrogen excretion (a marker of colonic fermentation) expressed as area under the curve (AUC)(0-630 min) was [median (range)] 6300 (1785-10800) ppm∙min for low-FODMAP rye bread and 10 635 (4215-13080) ppm∙min for regular bread (P = 0.028). Mean scores of gastrointestinal symptoms showed no statistically significant differences but suggested less flatulence after low-FODMAP bread consumption (P = 0.063). 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, pressure, or transit times between the breads. Gastric residence of SmartPill was slower than expected. SmartPill left the stomach in less than 5 h only during one measurement (out of 14 measurements in total) and therefore did not follow on par with the rye bread bolus.
Low-FODMAP rye bread reduced colonic fermentation vs regular rye bread. No difference was found in median values of intraluminal conditions of the gastrointestinal tract.
Core tip: Our study confirmed that low-FODMAP rye bread reduces colonic fermentation in irritable bowel syndrome (IBS) patients compared with regular rye bread. The observed correlation between increased intracolonic pressure and symptom severity underlines the central role of visceral sensitivity in IBS and suggests that some IBS symptoms might be exacerbated by any pathophysiological reason that leads to increased colonic pressure. The study also suggests that SmartPill might not be an optimal device to evaluate gastrointestinal circumstances during meal studies lasting less than 24 h, due to device’s inability to measure effects of a singular food bolus in a timely manner.