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

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. 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. 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 ([Delta]SDS) 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 ± 2.6 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. 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.