Abstract

Objective: To test the safety and effect on faecal microbiota of a formula with prebiotic oligosaccharides alone or in combination with acidic oligosaccharides in infants at the age of partial formula feeding. Patients and Methods: The study was a double-blind, placebo-controlled, randomised intervention trial in which 82 healthy, full-term, partially breast-fed children, from 1 week to 3 months old, were given 1 of the following formulae: whey-based formula (control group), whey-based formula with galacto- and long-chain fructo-oligosaccharides (scGOS/1cFOS group), or whey-based formula with galacto and long-chain fructo-oligosaccharides added with pectin derived acidic oligosaccharides (scGOS/1cFOS/pAOS group). Children were studied for the duration of the partial formula feeding period and every 2 weeks for 2 months after breast-feeding cessation. The total bacteria count and the proportion of 7 bacterial families were determined using in situ hybridisation coupled to flow cytometry. Results: The total bacterial count did not alter with time or type of feeding (9.9 +/- 0.1 log(10) cells per gram wet weight). Compared with the control group, there was an increase of the Bifidobacterium genus (P=0.0001), and a decrease of proportions for the Bacteroides group (P=0.02) and the Clostridium coccoides group (P=0.01) in both oligosaccharide groups. The proportion of bifidobacteria was significantly higher in the scGOS/1cFOS/pAOS compared with the scGOS/1cFOS group (P 0.01). Conclusions: Infant formulae appear to be clinically safe and effective on infant microbiota. They minimize the alteration of faecal microbiota after cessation of breast-feeding and promote bifidobacteria proportions, with a stronger effect when acidic oligosaccharides are present.