Inulin-type
fructans (beta(2,1)
fructans) extracted from chicory roots (Cichorium intybus) are
prebiotic food ingredients, which in the gut lumen are fermented to
lactic acid and SCFA. Research in experimental animal models revealed that
inulin-type
fructans have anticarcinogenic properties. A number of studies report the effects of
inulin-type
fructans on chemically induced pre-neoplastic lesions (ACF) or tumours in the colon of rats and mice. In twelve studies, there were twenty-nine individual treatment groups of which twenty-four measured
aberrant crypt foci (ACF) and five measured tumours. There was a significant reduction of ACF in twenty-one of the twenty-four treatment groups and of tumour incidence in five of the five treatment groups. Higher beneficial effects were achieved by synbiotics (mixtures of probiotics and
prebiotics), long-chain
inulin-type
fructans compared to short-chain derivatives, and feeding high-fat Western style diets.
Inulin-type
fructans reduced tumour incidence in APC(Min) mice in two of four studies and reduced growth and metastasising properties of implanted tumour cells in mice (four studies). The effects have been reported to be associated with gut flora-mediated fermentation and production of
butyrate. In human cells,
inulin-derived fermentation products inhibited cell growth, modulated differentiation and reduced
metastasis activities. In conclusion, evidence has been accumulated that shows that
inulin-type
fructans and corresponding fermentation products reduced the risks for
colon cancer. The involved mechanisms included the reduction of exposure to risk factors and suppression of tumour cell survival. Thus, this specific type of dietary fibre exerted both blocking agent and suppressing agent types of chemopreventive activities.