High level of
dietary fiber has been epidemiologically linked to protection against the risk for developing
colon cancer. The mechanisms of this protection are not clear. Fermentation of
dietary fiber in the colon results in production of for example
butyrate that has drawn attention as a chemopreventive agent.
Polydextrose, a soluble fiber that is only partially fermented in colon, was fermented in an in vitro colon simulator, in which the conditions mimic the human proximal, ascending, transverse, and distal colon in sequence. The subsequent fermentation metabolomes were applied on
colon cancer cells, and the gene expression changes studied.
Polydextrose fermentation down-regulated gene ontology classes linked with cell cycle, and affected number of metabolically active cells. Furthermore, up-regulated effects on classes linked with apoptosis, with increased
caspase 2 and 3 activity, implicate that
polydextrose fermentation plays a role in induction of apoptosis in
colon cancer cells. The up-regulated genes involved also key regulators of lipid metabolism, such as PPARα and PGC-1α. These results offer hypotheses for the mechanisms of two health benefits linked with consumption of
dietary fiber, reducing risk of development of
colon cancer, and
dyslipidemia.