Objective: The aim of the present study was to compare the effect of Bifidobacterium animalis subspecies lactis (B lactis) alone or with 90% galacto-oligosaccharide (GOS) and 10% fructo-oligosaccharide (FOS) on infections in infants.
Methods: In a multicenter trial, healthy, term, newborn infants ages 42 days or younger whose mothers had decided not to breast-feed beyond this age received infant and follow-on formulas containing B lactis (10 colony-forming units/g) + GOS/FOS (0.4 g/100 mL, intention-to-treat, n = 261) or B lactis alone (10⁷ colony-forming units/g, intention-to-treat, n = 267). Investigators accessed computer-generated randomization sequences via a remote server. Infants were exclusively fed formulas until 4 to 6 months of age and along with complementary feeding thereafter up to 12 months. The primary outcome was the mean number of annual infections reported by the investigators. Secondary outcomes were mean gains in anthropometric measurements, frequency of antibiotic use, and occurrence of adverse events based on investigators' records at each visit and gastrointestinal tolerance (daily stool frequency and consistency) and volume of formula intake recorded in 6-day diaries by parents.
Results: Mean ± standard deviation infection rates in infants followed up to 12 months (full analysis set) were 4.9 ± 3.2 per infant per year in the B lactis + GOS/FOS group (n = 219) and 4.5 ± 3.0 per infant per year in the B lactis group (n = 220; analysis of variance, P = 0.18). Mean daily weight gain was slightly lower in the B lactis + GOS/FOS than the B lactis group (16.1 ± 2.9 vs 16.6 ± 2.6 g/day, P = 0.046), but was not clinically significant. Other outcomes were not significantly different between groups.
Conclusions: Formulas containing B lactis + GOS/FOS did not reduce infection rates beyond those containing only B lactis.