Effect of arabinoxylo-oligosaccharides on proximal gastrointestinal motility and digestion in healthy volunteers

SummaryBackground & aimsBefore evaluating the effect of arabinoxylo-oligosaccharides (AXOS), a newly proposed prebiotic, on colonic metabolism, we evaluated its influence on proximal gastrointestinal motility [gastric emptying (GE) and oro-caecal transit time (OCTT)] and digestion of proteins and lipids.MethodsTen healthy volunteers each performed 2 13CO2-breath tests for assessing protein digestion and 2 for lipid digestion, each in the absence and presence of 2.2 g AXOS. To each test meal, 14C-labelled octanoate and inulin-14C-carboxylic acid were added for simultaneous measurement of GE and OCTT, respectively. Breath samples were collected and analysed with isotope ratio mass spectrometry (13C) or liquid scintillation (14C).ResultsAddition of AXOS to the lipid test meal did not influence lipid digestion. However, GE but not OCTT of the lipid test meal was significantly accelerated by ingestion of AXOS (p = 0.028). In the presence of AXOS, the rate of protein digestion proceeded slower but the overall extent of protein digestion after 5 h was not significantly different. GE and OCTT of the protein digestion test meal remained unchanged.ConclusionsAddition of a low dose of AXOS to a meal does not influence the supply of lipids and proteins to the colon. Therefore, possible effects of AXOS on the colonic metabolism should not be due to differences in proximal motility and digestion.