Effects of infant formula containing galacto-oligosaccharides on the intestinal microflora in infants

Objective To study the effect of a low level of galacto-oligosaccharides (GOS) on intestinal bifidobacteria and lactobacilli, and fermentation characteristics in term infants by comparing with human milk and a standard infant formula without GOS. Methods A total of 371 term infants from four hospitals of China were enrolled. The infants started with breast feeding. After 1-2 weeks, some of the infants were changed to feeding with formula milk and then were randomly assigned to two formula-feeding groups: with or without GOS supplementation (2.4 g/L). Growth, stool characteristics, and side effects were recorded in a 3-month-follow-up. Faecal samples were collected for analysis of intestinal bacteria (culture technique), acetic acid (gas chromatography) and pH (indicator strip) at postnatal 3 months. Results Compared with the formula-feeding group without GOS, the contents of bifidobacteria, lactobacilli and acetic acid and stool frequency increased, and faecal pH decreased significantly in the GOS-formula-feeding and the human milk group. There were no significant differences between the GOS-formula-feeding and the human milk groups. Supplementation with GOS did not lead to an increase in the incidence of crying, regurgitation and vomiting. Conclusions A supplementation of low levels of GOS in infant formula seemed to improve stool frequency, decrease faecal pH, and stimulate intestinal bifidobacteria and lactobacilli up to levels as found in breast-fed infants.