Objectives: The larger number of bifidobacteria in the intestine of breast-fed infants has been associated with their better health compared with formula-fed infants. We assessed the safety and tolerability of an experimental formula containing 2 x 10(7) colony-forming units of Bifidobacterium longum BL999 and 4 g/L of a prebiotic mixture containing 90% galacto-oligosaccharides and 10% fructo-oligosaccharides.
Methods: A 7-mo prospective, randomized, reference-controlled, double-blinded trial was performed in infants who were not breast fed after the 14th day of birth. One hundred thirty-eight infants were enrolled and assigned to receive the control or experimental formula until they were 112 d old. Mean weight gain (primary outcome) and recumbent length, head circumference, tolerability (gastrointestinal symptoms), and overall morbidity (secondary outcomes) were measured at 14, 28, 56, 84, and 112 d of age.
Results: Equivalence in mean weight gain between the two groups was shown. The treatment difference in the intention-to-treat and per-protocol populations were within the predefined equivalence boundaries of +/-3.9 g/d. No statistically significant difference in recumbent length, head circumference, or incidence of adverse events was found between the two groups. Infants in the experimental group had fewer incidences of constipation and had stool characteristics that suggest that the experimental formula was tolerated well. Furthermore, these infants showed a trend toward fewer respiratory tract infections.
Conclusions: The starter formula containing BL999 and galacto-oligosaccharides/fructo-oligosaccharides is safe and well-tolerated.