Prebiotic potential of L-sorbose and xylitol in promoting the growth and metabolic activity of specific butyrate-producing bacteria in human fecal culture.
Level 5 - mechanism / opinion, no new human data
In vitro bench study using human fecal cultures and isolated bacterial strains.
PubMed 27810878 · doi:10.1093/femsec/fiw227
What was done
Fecal suspensions collected from 5 healthy male donors were incubated anaerobically in vitro with various low-digestible carbohydrates (LDCs), including L-sorbose and xylitol. Microbial shifts were evaluated using 16S rRNA gene-based denaturing gradient gel electrophoresis (DGGE). In addition, candidate butyrate producers were isolated via agar plate culture, and 12 representative colonic butyrate-producing bacterial species were screened for butyrate production when cultured with L-sorbose or xylitol.
What was found
L-sorbose and xylitol promoted butyrate formation in fecal cultures, accompanied by an increased abundance of bacteria closely related to Anaerostipes hadrus and/or Anaerostipes caccae (quantitative yield numbers not reported in the abstract). Two A. hadrus strains capable of producing butyrate from both carbohydrates were isolated from two donors. Of the 12 representative colonic butyrate-producing species tested, only A. hadrus and A. caccae showed augmented butyrate production in the presence of L-sorbose or xylitol.
Why it matters
This study identifies Anaerostipes species as potential microbial mediators through which non-digestible carbohydrates like xylitol and L-sorbose could stimulate colonic butyrate production.
Limits
The study is entirely in vitro, which cannot account for human digestive absorption, motility, or host mucosal interactions. The donor pool was limited to 5 healthy males, and the abstract provides no quantitative numbers or statistical measures for the increase in butyrate production.
Cited by
- supports Xylitol is fermented in the digestive tract to form butyrate, a protective short-chain fatty acid.