Dose-response effect of arabinoxylooligosaccharides on gastrointestinal motility and on colonic bacterial metabolism in healthy volunteers.
OBJECTIVE
Arabinoxylooligosaccharides (AXOS) are non-digestible in the upper gastrointestinal tract and have been shown to exert prebiotic effects in animals. The aim of this study was to characterize the influence of AXOS with an average degree of polymerization of 15 and an average degree of arabinose substitution of 0.26 (AXOS-15-0.26) on gastrointestinal motility and colonic bacterial metabolism in healthy human volunteers.


METHODS
Twelve healthy volunteers received five test meals, containing different amounts of AXOS-15-0.26, with one week intervals between each test meal. Breath tests were used to measure gastric emptying rate, oro-cecal transit time (OCTT) and hydrogen excretion. Colonic bacterial metabolism was estimated using the biomarkers lactose-[(15)N, (15)N']-ureide ((15)N-LU) and p-cresol.


RESULTS
Gastric emptying and OCTT were not influenced by addition of varying amounts of AXOS-15-0.26. Administration of 2.2g or 4.9 g AXOS-15-0.26 significantly decreased the urinary (15)N-excretion (respectively p = 0.008 and p = 0.035) as compared to the baseline, whereas fecal (15)N-excretion was significantly increased (respectively p = 0.034 and p = 0.019). This shift from urinary to fecal (15)N-excretion suggests a higher uptake or incorporation by bacteria due to the stimulation of colonic bacterial growth and/or metabolic activity. Furthermore, a significant increase in hydrogen excretion after administration of 2.2g (p = 0.002) and 4.9 g (p = 0.004) AXOS-15-0.26 was observed. No influence on urinary p-cresol excretion was observed.


CONCLUSIONS
These findings suggest that a minimal dose of 2.2g AXOS-15-0.26 favorably modulates the colonic bacterial metabolism in healthy humans. However, long term studies are required to confirm a possible prebiotic effect.
Cloetens
Lieselotte
L
Department of Gastrointestinal Research, University Hospital Gasthuisberg, Belgium.
De Preter
Vicky
V
Swennen
Katrien
K
Broekaert
Willem F
WF
Courtin
Christophe M
CM
Delcour
Jan A
JA
Rutgeerts
Paul
P
Verbeke
Kristin
K
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003106:Colon / Q000378:metabolism* / Q000382:microbiology*; D004305:Dose-Response Relationship, Drug; D002523:Edible Grain; D005260:Female; D005527:Food, Fortified; D005769:Gastrointestinal Motility / Q000187:drug effects*; D005772:Gastrointestinal Transit; D006801:Humans; D007554:Isotopes / Q000032:analysis; D008297:Male; D009844:Oligosaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D019936:Probiotics / Q000494:pharmacology*; D055815:Young Adult
D015415:Biomarkers; D007554:Isotopes; D009844:Oligosaccharides; D010936:Plant Extracts