This summary has been adapted from Molecular ecological analysis of fecal bacterial populations from term infants fed formula supplemented with selected blends of prebiotics. Applied and Environmental Microbiology (2009) by Noriko Nakamura et al
Oligosaccharides account for the third largest constituent of human breast milk, after lactose and lipids, while comparatively, cow’s milk-based formula contains a relatively low level. Research has observed that this difference can affect the microbiota in the lower gastrointestinal tract. In infants fed with breast milk, Lactobacilli and bifidobacterial are the most abundant types of microbiota, which help to metabolise prebiotics and thereby improve the health of the child (1,2). As such, investigations have been performed to examine the effects of supplementing infant formula with different mixtures prebiotics, such as polydextrose (PDX), galactooligosaccharide (GOS) or lactulose (LOS).
A study performed in the United States compared a group of breast-fed infants (BF group, n=30) and four groups of infants that were fed formulas. For an initial run-in period of seven days, all formula-fed infants were given the same control formula with no supplements. Following this period, the infants were stratified into groups and received the control formula with one of a number of prebiotic supplement blends. These were:
- Supplemented with PDX and GOS (4g/litre) (PG4 group; n=27)
- Supplemented with PDX, GOS, and LOS (4g/litre) (PGL4 group; n=27)
- Supplemented with PDX, GOS, and LOS (8g/litre) (PGL4 group; n=27)
- No supplement added (control group, n=25)
This multicentre, double-blinded, controlled study was performed with infants that were healthy term and aged 13-92 days. Faecal samples were collected from participants and analysed using quantitative polymerase chain reaction (qPCR) and fluorescence in situ hybridization (FISH) techniques. Bacterial communities were profiled with 16S rRNA gene PCR-denaturing gradient gel electrophoresis (DGGE). Samples were collected at baseline (day 1), day 14 and day 28. Furthermore, the degree of formula tolerance and any adverse events were also reported.
Of the initial cohort, 117 infants were available for the final analysis (BF = 30; Control = 25; PG4 = 27; PGL4 = 27; PGL8 = 25) with comparable groups in terms of gender and age distributions. It was observed that the BF group produced softer consistency stools, but there was no difference between any of the formula-fed groups. Equally, there were no differences between the groups in terms of fussiness or adverse events. All the formulas were tolerated well. The tests used to identify the microbiota elicited few differences between feeding groups at the difference time points.
Using the DGGE profiles that were performed at each time point, a CS value was calculated for each infant, which gave an indication of the stability of the gastrointestinal bacteria. While there was no effect across feeding groups, in each of the three supplemented-formula groups and the BF group, those aged 50 days or younger at the start of the study had significantly lower CS values, indicative of less stability in the bacteria community profiles. This trend was not observed in the control group, however.
These age-related findings suggest that prebiotic-supplemented formulas may have an increased effects on the gastrointestinal microbiota when introduced earlier in infancy. This correlated with the trend observed in the BF group, suggesting that the addition of these supplements to formula helped to replicate the human milk’s effect on gut bacterial profiles. The degree of this influence and the effects of different supplemental blends are recommended to be researched further to provide greater clarity to this observation.
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- Ziegler, E., J. A. Vanderhoof, B. Petschow, S. H. Mitmesser, S. I. Stolz, C. L. Harris, and C. L. Berseth. 2007. Term infants fed formula supplemented with selected blends of prebiotics grow normally and have soft stools similar to those reported for breast-fed infants. J. Pediatr. Gastroenterol. Nutr. 44:359–364.