This was a prospective, randomised, double blind, placebo-controlled study, investigating whether probiotics affect the occurrence of infections in infants in day care.

201 healthy children, aged 4–10 months, were studied for 12 weeks in three different groups: They were given formula with Lactobacillus reuteri ATCC 55730 or Bifidobacterium lactis Bb-12, or formula without probiotics (control).

Probiotics resulted in significantly fewer infections compared to the placebo, measured by the number of febrile episodes and episodes of gastrointestinal infection. Lactobacillus reuteri, however, had a significantly superior effect compared to B. lactis and the control group: there were significantly fewer doctors’ visits, less use of antibiotics, and fewer absent days from day care in the Lactobacillus reuteri group. 

Conclusion: The addition of probiotics to infant formula had a significantly positive effect on the incidence of common infections in children in day care, with superior effect shown for Lactobacillus reuteri. There were no safety issues during the three months of the study.