The effect of a prebiotic supplemented formula on growth and stool microbiology of term infants

Abstract

Background The intestinal flora of breast-fed infants is generally dominated by bifidobacteria which have beneficial properties. Their presence is due to various compounds of breast milk including prebiotic substances. Aim This prospective, double blind, study compared the growth, acceptability and the proportion of bifidobacteria and clostridia in the stool flora of bottle-fed infants randomized to receive a formula with a specific mixture of 0.4 g/100 ml prebiotic galacto- and long-chain fructooligosaccharides or the same formula without added prebiotics. Methods Within 0–14 days after birth at term, healthy bottle-fed infants were enrolled to receive either a prebiotic formula or a standard formula. At recruitment anthropometric measurements were done. These were repeated at the age of 6 and 12 weeks. Stool samples were taken at inclusion and at the age of 6 weeks. The number of bifidobacteria and clostridia was determined by fluorescent in situ hybridization. Results There was good tolerance of the prebiotic formula. Somatic growth was similar in the two groups. Stool frequency was significantly higher in the prebiotic group ( P = 0.031). Infants in the prebiotic group had also softer stools as compared to the control group ( P = 0.026). Baseline values of microorganisms at study entry were similar. The percentage of faecal clostridia at the completion of the study was significantly lower in the prebiotic group ( P = 0.042), while the proportion of faecal bifidobacteria was higher in the prebiotic group as compared to the control group. However this difference did not reach statistical significance ( P = 0.262). The percentage of E. coli was lower in the prebiotic group but again this did not reach statistical significance ( P = 0.312). Conclusion An infant formula containing prebiotic oligosaccharides is well tolerated, leads to normal somatic growth and suppresses the numbers of clostridia in the faeces with a trend for higher percentage of stool bifidobacteria and lower percentage of E. coli.