Effects of Feeding Bifidobacterium longum and Inulin on Some Gastrointestinal Indices in Human Volunteers

Interest in consumption of probiotic and prebiotics (indigestible oligosaccharides) to improve human gastrointestinal health is increasing. Consumption of beneficial probiotic bacteria combined with oligosaccharides may provide enhanced gastrointestinal benefits and improvements in internal health. The objective of this study was to evaluate the effectiveness of administering Bifidobacterium longum 1941 or B. longum BB536 and inulin to healthy, adult volunteers over 2-wk to observe changes in gastrointestinal indices (bacterial counts in stool, stool defecation frequency and consistency, and in organic acids, β-glucuronidase and β-glucosidase enzyme concentration, pH and moisture). A randomised, double-blind and placebo-controlled parallel group comparison was carried out. Subjects were randomly assigned to receive 25 mg of freeze-dried bacterial preparation containing ≥ 1 × 10 1 0 cfu/g of either B. longum 1941 and 475 mg inulin (n = 10), B. longum BB536 and 475 mg inulin (n = 10) or a placebo containing 475 mg inulin (n = 10). Efficacy was based on comparison of initial values of gastrointestinal indices with final values. No significant difference between the baseline and the final reading among the three treatment groups was observed on bacterial counts, defecation frequency, stool consistency, pH, enzyme and organic acid concentrations or moisture percentage of stools. However, levels of butyric acid increased after subjects consumed probiotic capsules. No subjects reported worsening in gastrointestinal health after consumption of probiotic capsules. These results indicate that the administration of B. longum 1941 and B. longum BB536 did not significantly alter the intestinal environment, defecation frequency and faecal characteristics of healthy, human subjects. These results were possibly due to the short duration of the study and the participation of healthy, adult populations consuming probiotic bacteria and prebiotics.