Effects of wheat bran extract rich in arabinoxylan oligosaccharides and resistant starch on overnight glucose tolerance and markers of gut fermentation in healthy young adults.

Purpose: Specific combinations of dietary fiber (DF) have been observed to result in improved glucose tolerance at a subsequent standardized breakfast. Arabinoxylan oligosaccharides (AXOS) are considered as DF with prebiotic potential, but so far no studies have investigated their metabolic effects in humans. This randomized cross-over study evaluated the overnight impact of breads containing AXOS-rich wheat bran extract and resistant starch (RS, Hi-Maize), separately or combined, on glucose tolerance, related metabolic parameters and markers of gut fermentation in healthy subjects. Methods: Evening reference and test products were: (1) reference white wheat flour bread (WWB), WWB supplemented with (2) AXOS and RS (WWB + AXOS + RS), (3) an increased content of either AXOS (WWB + hiAXOS) or (4) RS (WWB + hiRS). At the subsequent standardized breakfast, blood was sampled for 3 h to monitor glucose, insulin, nonesterified fatty acids, glucagon-like peptide (GLP)-1 and GLP-2. Breath hydrogen (H) and short chain fatty acids (SCFA) were measured as markers of gut fermentation, and subjective appetite was rated using visual analog scales. Results: Dose-dependent decreases in glucose responses were observed with increased AXOS over the duration of 3 h. Insulin sensitivity index was improved in the morning after the WWB + hiAXOS evening meal. An increase in breath H concentration and circulating SCFA was observed in the morning after both evening meals containing AXOS. Conclusion: The present study indicates that AXOS have the potential of improving glucose tolerance in an overnight perspective and suggested mechanisms are improved insulin sensitivity and increased gut fermentation. [ABSTRACT FROM AUTHOR]