Effects of the consumption of Bifidobacterium lactis HN019 (DR10^TM) and galacto-oligosaccharides on the microflora of the gastrointestinal tract in human subjects

Abstract 

The effects of dietary consumption of milk derived oligosaccharides and a probiotic bacterium Bifidobacterium lactis HN019 (also known as DR10^TM) on the microbial composition of the gastrointestinal tract of human subjects was examined using a randomized, double blind, placebo-controlled study design. Thirty subjects (age range 20–60 years) were divided randomly into three groups. After two weeks of a pre-intervention period, volunteers in group one consumed a reconstituted milk containing 2.4 g of galacto-oligosaccharides per day, volunteers in group two consumed reconstituted milk containing 3 × 10¹⁰ CFU of B. lactis HN019 per day, and group three volunteers consumed reconstituted milk without galacto-oligosaccharides or probiotic bacteria. The feeding period continued for four weeks followed by a wash out period of two weeks. Faecal samples were collected at weekly intervals and analysed for eight major groups of microbes associated with human gastrointestinal tract. Subjects receiving reconstituted milk containing either galacto-oligosaccharides or probiotic bacteria (B. lactis HN019) exhibited a significant increase in the faecal counts of both lactobacilli (p < 0.004) and bifidobacteria (p < 0.0002). In comparison, little or no changes were observed in lactobacilli and bifidobacteria counts in subjects who consumed reconstituted milk without supplementation with either galacto-oligosaccharides or probiotic B. lactis HN019 (placebo control group). Furthermore, B. lactis HN019 survived the digestion through human gastrointestinal tract and colonised transiently. It is believed that desirable bacteria including members of the genera bifidobacterium and lactobacillus, have a positive impact on human health. The results presented in this study demonstrate that dietary supplementation with B. lactis HN019 or galacto-oligosaccharides increases the proportion of bifidobacterium and lactobacillus in the human gastrointestinal tract and hence may improve human health.

Keywords: Bifidobacterium lactis, DR10^TM, Faecal microflora, Galacto-oligosaccharides, Gastrointestinal tract, Lactobacilli, Prebiotics, Probiotics