Research
Beneficial Bacteria
Part 3

Effect of lactobacilli, bifidobacteria and inulin on the formation of aberrant crypt foci in rats

Abstract

Bolognani F, Rumney CJ, Pool-Zobel BL, Rowland IR.

TNO-BIBRA International, Carshalton, Surrey, UK.

BACKGROUND: Our studies were aimed at investigating the effect of lactic acid producing bacteria (LAB) or inulin, a natural source of non-digestible oligosaccharides derived from chicory, on the induction by carcinogens of aberrant crypt foci (ACF) in the colon, which are considered to be early precursor lesions of neoplasia. METHODS: Strains of Bifidobacterium longum, Lactobacillus casei and Lactobacillus acidophilus were administered to rats fed a purified high starch diet, under a variety of treatment protocols including daily gavage, via the drinking water and in the diet. The rats were treated with methyl-N-nitrosourea, 1,2-dimethylhydrazine, or azoxymethane (AOM) to induce ACF. RESULTS: In general, no consistent significant changes in ACF numbers were detected in these experiments. In one study, the basal diet of the rats was changed to one containing a higher level of fat (corn oil). Under these conditions, a significant decrease in AOM-induced colonic ACF was seen in rats given L. acidophilus or inulin. In a concurrent group of animals fed a low fat diet, no significant decrease in ACF was observed. CONCLUSIONS: The results indicate that the type of diet fed can influence the detection of protective effects of LAB and oligosaccharides and that against the background of a diet with a level of fat typical of a Western diet, evidence for a protective effect of L. acidophilus and inulin towards colon cancer was obtained.