Effects of Bifidobacterium sp fermented milk ingested with or without inulin on colonic bifidobacteria and enzymatic activities in healthy humans.

OBJECTIVE

To assess in healthy humans the effects of prolonged ingestion of Bifidobacterium sp fermented milk (BFM) with or without inulin on fecal bifidobacteria and some bacterial enzymatic activities.

DESIGN

Twelve volunteers randomly divided into two groups were studied for three consecutive periods. During the ingestion period, they received BFM in association with ether 18g/d inulin or placebo in three oral doses for 12 days. Stools were regularly collected for bacteriological analysis.

SETTING

Clinical Nutrition Unit, Hopital Saint-Lazare, Paris.

RESULTS

The administration of BFM with placebo led to an increase in total bifidobacteria (indigenous and exogenous) (P < 0.01) and exogenous bifidobacteria (P < 0.01) and a decrease in beta-glucuronidase activity (P < 0.01). Simultaneous administration of BFM and inulin led to an increase in total bifidobacteria (P < 0.01) and exogenous bifidobacteria (P < 0.01), but had no effect on beta-glucuronidase activity. No differences were found for fecal concentrations reached by exogenous and indigenous bifidobacteria between the two groups. Administrated alone or with inulin, BFM did not change fecal total anaerobe counts, pH, nitrate reductase, nitroreductase and azoreductase activities.

CONCLUSIONS

Administration of BFM substantially increases the proportion of bifidobacteria in the colonic flora, but the concurrent administration of inulin does not enhance this effect.