Abstract
Background: Dietary fiber intake can modulate colonic transit time and fermentation, leading to digestive benefits. A novel telemetric gas-sensing capsule can measure gastrointestinal transit time and colonic fermentation in real time by directly measuring volatile molecules in the lumen.
Research Objective: The primary outcome was to explore the effect of fiber-rich foods on colonic transit and fermentation profile.
Methods: Two studies examined the impact of fiber-rich foods on colonic transit and fermentation over four weeks. Study A, an open-label parallel trial, involved 60 adults with chronic constipation who consumed two green kiwifruit (5 g fiber) or a maltodextrin (~0 g) daily. Study B, a doubleblinded cross-over trial, involved 60 healthy adults with low habitual fiber intake who consumed bread fortified with defatted rice bran fortified (8-11 g) or white bread (2-3 g) daily. In both studies, participants ingested the gas-sensing capsule, and colonic transit time and concentrations of colonic hydrogen (H2) and carbon dioxide (CO2) were assessed.
Results: No significant differences (p >0.05) were found between control and intervention groups in Study A and Study B in colonic transit and colonic concentrations of H2 and CO2. However, both studies observed non-significant but distinct regional colonic H2 and CO2 concentration patterns between intervention groups. In Study A, the kiwifruit group had higher Hâ‚‚ concentration and lower CO2 levels towards the distal colon, while the maltodextrin group had the opposite. In Study B, which remains blinded, one intervention had elevated H2 and CO2 concentrations across all colonic regions, while the other intervention had higher H2 and CO2 concentrations in the proximal colon but decreased distally.
Discussion: The studies utilised novel technology to show qualitative changes to regional patterns of H2 and CO2 in the colon. Further adequately powered studies are needed to understand these observations better using this novel technology.