A randomised, double-blind, placebo controlled cross-over study to determine the gastrointestinal effects of consumption of arabinoxylan-oligosaccharides enriched bread in healthy volunteers.
BACKGROUND
Prebiotics are food ingredients, usually non-digestible oligosaccharides, that are selectively fermented by populations of beneficial gut bacteria. Endoxylanases, altering the naturally present cereal arabinoxylans, are commonly used in the bread industry to improve dough and bread characteristics. Recently, an in situ method has been developed to produce arabinoxylan-oligosaccharides (AXOS) at high levels in breads through the use of a thermophilic endoxylanase. AXOS have demonstrated potentially prebiotic properties in that they have been observed to lead to beneficial shifts in the microbiota in vitro and in murine, poultry and human studies.


METHODS
A double-blind, placebo controlled human intervention study was undertaken with 40 healthy adult volunteers to assess the impact of consumption of breads with in situ produced AXOS (containing 2.2 g AXOS) compared to non-endoxylanase treated breads. Volatile fatty acid concentrations in faeces were assessed and fluorescence in situ hybridisation was used to assess changes in gut microbial groups. Secretory immunoglobulin A (sIgA) levels in saliva were also measured.


RESULTS
Consumption of AXOS-enriched breads led to increased faecal butyrate and a trend for reduced iso-valerate and fatty acids associated with protein fermentation. Faecal levels of bifidobacteria increased following initial control breads and remained elevated throughout the study. Lactobacilli levels were elevated following both placebo and AXOS-breads. No changes in salivary secretory IgA levels were observed during the study. Furthermore, no adverse effects on gastrointestinal symptoms were reported during AXOS-bread intake.


CONCLUSIONS
AXOS-breads led to a potentially beneficial shift in fermentation end products and are well tolerated.
Department of Food and Nutritional Sciences, University of Reading, Reading, RG6 6AP, United Kingdom. g.e.walton@rdg.ac.uk
Gemma E
GE
Walton
Congyi
C
Lu
Isabel
I
Trogh
Filip
F
Arnaut
Glenn R
GR
Gibson
D000293:Adolescent; D000328:Adult; D001644:Bifidobacterium / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D001939:Bread / Q000009:adverse effects / Q000032:analysis; D018592:Cross-Over Studies; D004311:Double-Blind Method; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000032:analysis / Q000378:metabolism; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D005285:Fermentation; D005503:Food Additives / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009844:Oligosaccharides / Q000009:adverse effects / Q000032:analysis / Q000378:metabolism*; D056692:Prebiotics / Q000009:adverse effects / Q000032:analysis; D014990:Xylans / Q000009:adverse effects / Q000032:analysis / Q000378:metabolism*; D055815:Young Adult
D005232:Fatty Acids, Volatile; D005503:Food Additives; D009844:Oligosaccharides; D056692:Prebiotics; D014990:Xylans; C085118:arabinoxylan; D043364:Endo-1,4-beta Xylanases