Growth during the first 6 months of life in infants using formula enriched with Lactobacillus rhamnosus GG: double-blind, randomized trial.

BACKGROUND: Probiotic bacteria have beneficial effects on the immune system and gastrointestinal tract, but the impacts of their long-term consumption on health and growth in early infancy are not well documented. The aim of this study was to evaluate the influence of Lactobacillus rhamnosus GG (LGG)-enriched formula on growth and faecal microflora during the first 6 months of life in normal healthy infants. MATERIALS AND METHODS: One hundred and twenty healthy infants (up to 2 months) received LGG-supplemented formula or regular formula in a double-blind, randomized manner until the age of 6 months. Weight, length and head circumference were measured monthly and transformed into standard deviation scores (SDS). Faecal samples were obtained from a random sample of infants (n=25) at entry and at the end of the study. RESULTS: One hundred and five infants (51 in the LGG group) completed the study. Children receiving LGG-supplemented formula grew better: their changes in their length and weight SDS (DeltaSDS) at the end of the study were significantly higher than those receiving regular formula (0.44+/- 0.37 versus 0.07+/- 0.06, P< 0.01 and 0.44+/- 0.19 versus 0.07+/- 0.06, P< 0.005, respectively). The LGG group had a significant, higher defecation frequency 9.1+/-2.06 versus 8.0+/- 2.8 (P<0.05). More frequent colonization with lactobacilli was found in the LGG group, 91% versus 76% (P<0.05) at the end of the study. CONCLUSIONS Infants fed with LGG-enriched formula grew better than those fed with regular formula. Further studies are necessary to clarify the mechanism of LGG in infant growth.