Results from tests with two lab models – the simulator of the intestinal microbial ecosystem (SHIME) model and the dynamic TNO in vitro model of the colon (TIM-2) – indicated that the arabinoxylan increased select populations of bifidobacteria.
“Even if a direct extrapolation of the present study to humans is not straightforward, our results suggest that besides inulin, long-chain arabinoxylan seem to fulfill the requirements to be considered a promising prebiotic compound and that they might confer beneficial health effects through gut microbiome modulation, potentially in a more specific and potent manner as compared to inulin,” wrote the researchers in the Journal of Agricultural and Food Chemistry.
A prebiotic is defined as “a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health” (M. Roberfroid, J. Nutr., 2007, Vol. 137, pp. 830S-837S).
Scientists from Ghent University in Belgium and TNO Environmental and Life Sciences in the Netherlands explained that only a limited number of studies have investigated the potential prebiotic activity of wheat-derived long-chain arabinoxylan.
Using the arabinoxylan from Bioactor, the researchers compared this with inulin from Cosucra (Fibruline instant). The arabinoxylan was found to stimulate growth of Bifidobacterium longum, while inulin stimulated other bifidobacteria including Bifidobacterium adolescentis, they said.
Differences between the fibers were also observed in terms of the production of short chain fatty acids (SCFA), with the long-chain arabinoxylan increasing levels of propionate, while inulin promoted butyrate production.
“This health-promoting metabolite [propionate] has been shown to lower cholesterol absorption,” explained the researchers. “Moreover, it can be absorbed from the intestine and, via bloodstream, reach the liver, where it has been associated with reduced cholesterol synthesis and improved insulin sensitivity in humans and rats.”
Additional results from the SHIME experiment indicated that the effects observed from the long-chain arabinoxylan were more persistent during a two week period without any fiber addition, a result which supported recent animal data from experiment with germfree rats inoculated with human feces.
“Using two distinct in vitro models for the human gut, we show that a specific concentrate of water-extractable long-chain arabinoxylan and the well-established prebiotic inulin may be complementary as they both induced specific fermentation patterns within the intestinal microbiota with specific potential health benefits,” wrote the researchers.
“Future research should establish how widespread these specific microbial responses to long-chain arabinoxylan and inulin are among different human subjects.”
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, doi: 10.1021/jf4021784
“Different Human Gut Models Reveal the Distinct Fermentation Patterns of Arabinoxylan versus Inulin”
Authors: P. Van den Abbeele, K. Venema, T. Van de Wiele, W. Verstraete, S. Possemiers