Consumption of Breads Containing In Situ–Produced Arabinoxylan Oligosaccharides Alters Gastrointestinal Effects in Healthy Volunteers132

Arabinoxylan oligosaccharides (AXOS) are studied as food compounds with prebiotic potential. Here, the impact of consumption of breads with in situ-produced AXOS on intestinal fermentation and overall gastrointestinal characteristics was evaluated in a completely randomized, double-blind, controlled, cross-over study. Twenty-seven healthy volunteers consumed 180 g of wheat/rye bread with or without in situ-produced AXOS (WR+ and WR-, respectively) daily for 3 wk. Consumption of WR+ corresponded to an AXOS intake of ~2.14 g/d. Refined wheat flour bread without AXOS (W-) (180 g/d) was provided during the 3-wk run-in and wash-out periods. At the end of each treatment period, participants collected urine for 48 h as well as a feces sample. Additionally, all participants completed a questionnaire about stool characteristics and gastrointestinal symptoms during the last week of each period. Urinary phenol and p-cresol excretions were significantly lower after WR+ intake compared to WR-. Consumption of WR+ significantly increased fecal total SCFA concentrations compared to intake of W-. The effect of WR+ intake was most pronounced on butyrate, with levels 70% higher than after consumption of W- in the run-in or wash-out period. Consumption of WR+ tended to selectively increase the fecal levels of bifidobacteria (p = 0.06) relative to consumption of W-. Stool frequency increased significantly after intake of WR+ compared to WR-. In conclusion, consumption of breads with in situ-produced AXOS may favorably modulate intestinal fermentation and overall gastrointestinal properties in healthy humans.