Objectives: The intestinal flora of breast-fed infants is generally dominated by Bifidobacteria. We aimed to investigate whether an infant formula supplemented with galacto-oligosaccharides and fructo-oligosaccharides (GOS/FOS) is able to establish a bifido-dominant microflora, not only in numbers but also with respect to the metabolic activity in the colon.
Methods: Two groups of infants fed infant formula with 0.8 g/100 ml GOS/FOS in a ratio of 9:1 (OSF group), or control formula (SF group) were evaluated in a randomised, double blind, placebo controlled intervention study. A breast-fed group was studied in parallel. At study onset and after 4 and 6 weeks, faecal samples were examined for the number of bifidobacteria, pH, short chain fatty acids and lactate.
Results: After 6 weeks, the mean proportion of bifidobacteria was significantly higher in the OSF group (59.6% versus 49.5% in the SF group; P < 0.05). Compared with controls, infants in the OSF group had a lower stool mean pH and an increased proportion of acetate and a decreased proportion of propionate. The mean pH in the OSF and SF groups were 5.7 and 6.3, respectively (P < 0.001).
Conclusions: The addition of the prebiotic GOS/FOS mixture to an infant formula has a stimulating effect on the growth of bifidobacteria and on the metabolic activity of the total intestinal flora. The changes in short chain fatty acids, lactate and pH in the prebiotic group represent a fermentation profile that is closer to that observed in breast-fed infants compared to infants fed control formula.