Effects of infant formula containing a mixture of galacto- and fructo-oligosaccharides or viableBifidobacterium animalison the intestinal microflora during the first 4 months of life

Abstract

Adding prebiotics or probiotics to infant formula to improve the intestinal flora of formula-fed infants is considered to be a major innovation. Several companies have brought relevant formulations onto the market. However, comparative data on the effects of pre- and probiotics on the intestinal microflora of infants are not available. The present study aimed to compare the effects of infant formula containing a mixture of galacto- and fructo-oligosaccharides or viableBifidobacterium animalison the composition and metabolic activity of the intestinal microflora. Before birth, infants were randomised and double blindly allocated to one of three formulas. The prebiotic (GOS/FOS) group (n19) received regular infant formula supplemented with a mixture of galacto-oligosaccharides and fructo-oligosaccharides (6g/l). The probiotic (Bb-12) group (n19) received the same formula supplemented with 6·0×1010viable cells ofB. animalisper litre. The standard group (n19) received non-supplemented regular formula. A group of sixty-three breast-fed infants was included as a reference group. Faecal samples were taken at postnatal day 5 and 10, and week 4, 8, 12 and 16. Compared with the groups fed Bb-12 and standard formula, the GOS/FOS formula group showed higher faecal acetate ratio (69·7% (sem 2·7), 69·9% (sem 3·9) and 82·2% (sem 5·3);P<0·05) and lactate concentration (11·3 (sem 7·9), 3·1 (sem 2·3) and 34·7 (sem 10·7) mmol/kg faeces) and lower pH (6·6 (sem 0·2), 7·1 (sem 0·2) and 5·6 (sem 0·2);P<0·05) at 16 weeks. Differences in percentage of bifidobacteria between the GOS/FOS (59·2% (sem 7·7)), Bb-12 (52·7% (sem 8·0)) and the standard (51·8% (sem 6·4)) groups were not statistically significant at 16 weeks. Feeding infants GOS/FOS formula resulted in a similar effect on metabolic activity of the flora as in breast-fed infants. In the Bb-12 group, composition and metabolic activity of the flora were more similar to those of the standard group.