title: Bifidogenic effect of whole-grain wheat during a 12-week energy-restricted dietary intervention in postmenopausal women.
abstract: OBJECTIVE
  Consumption of whole-grain products is known to have beneficial effects on human health. The effects of whole-grain products on the intestinal microbiota and intestinal integrity have, however, only been studied limitedly. We investigate changes of the human gut microbiota composition after consumption of whole-grain (WW) or refined wheat (RW) and further study effects on gut wall integrity.
  
  
  METHODS
  Quantitative PCR was used to determine changes in the gut bacterial composition in postmenopausal women following a 12-week energy-restricted dietary intervention with WW (N=38) or RW (N=34). Intestinal integrity was determined by measuring trans-epithelial resistance (TER) across a Caco-2 cell monolayer, following exposure to faecal water.
  
  
  RESULTS
  No significant differences in microbiota composition were observed between the two dietary groups; however, the whole-grain intervention increased the relative abundance of Bifidobacterium compared to baseline, supporting a prebiotic effect of whole-grain wheat. Faecal water increased TER independent of dietary intervention, indicating that commensal bacteria produce metabolites that generally provide a positive effect on intestinal integrity. Combining microbiota composition data from the run-in period with its effect on TER revealed a tendency for a negative correlation between the relative abundance of Bifidobacterium and TER (P=0.09). This contradicts previous findings but supports observations of increased Salmonella infection in animal models following treatment with bifidogenic prebiotics.
  
  
  CONCLUSIONS
  The present study shows that whole-grain wheat consumption increases the abundance of bifidobacteria compared to baseline and may have indirect effects on the integrity of the intestinal wall.
authors.affiliation: Division of Food Microbiology, National Food Institute, Technical University of Denmark, Søborg, Denmark.
authors.forename: E G
authors.initials: EG
authors.lastname: Christensen
authors.forename: T R
authors.initials: TR
authors.lastname: Licht
authors.forename: M
authors.initials: M
authors.lastname: Kristensen
authors.forename: M I
authors.initials: MI
authors.lastname: Bahl
mesh_terms: D001644:Bifidobacterium / Q000235:genetics / Q000254:growth & development*; D018938:Caco-2 Cells; D031204:Caloric Restriction; D004269:DNA, Bacterial / Q000032:analysis; D004032:Diet; D017097:Electric Impedance; D004848:Epithelium / Q000502:physiology; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007422:Intestines / Q000382:microbiology; D064307:Microbiota; D017698:Postmenopause; D056692:Prebiotics; D012639:Seeds; D014908:Triticum
chemical_list: D004269:DNA, Bacterial; D056692:Prebiotics