title: Long-term consumption of infant formulas containing live probiotic bacteria: tolerance and safety.
abstract: BACKGROUND
  Nonpathogenic live bacteria are consumed as food by many children, particularly in the form of yogurt. The tolerance and safety of long-term consumption of specific types and strains of probiotic bacteria are not well documented.
  
  
  OBJECTIVE
  The goal was to evaluate tolerance to formulas containing 2 levels of probiotic supplementation and effects on growth, general clinical status, and intestinal health in free-living healthy infants.
  
  
  METHODS
  This was a prospective, double-blind, randomized, placebo-controlled study of healthy infants aged 3-24 mo. Infants were assigned to receive a standard milk-based formula containing 1 x 10(7) colony-forming units (CFU)/g each of Bifidobacterium lactis and Streptococcus thermophilus, formula containing 1 x 10(6) CFU/g each of B. lactis and S. thermophilus, or unsupplemented formula. Clinical outcomes included formula intake, gastrointestinal tolerance, anthropometric measures, daycare attendance, and history of illness.
  
  
  RESULTS
  One hundred eighteen infants aged ( +/- SD) 7.0 +/- 2.9 mo at enrollment consumed formula for 210 +/- 127 d. There were no significant differences in age, sex, formula consumption, or length of study between groups. The supplemented formulas were well accepted and were associated with a lower frequency of reported colic or irritability (P < 0.001) and a lower frequency of antibiotic use (P < 0.001) than was the unsupplemented formula. There were no significant differences between groups in growth, health care attention seeking, daycare absenteeism, or other health variables.
  
  
  CONCLUSIONS
  Long-term consumption of formulas supplemented with B. lactis and S. thermophilus was well tolerated and safe and resulted in adequate growth, reduced reporting of colic or irritability, and a lower frequency of antibiotic use.
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. saavedramail@earthlink.net
authors.forename: Jose M
authors.initials: JM
authors.lastname: Saavedra
authors.forename: Adel
authors.initials: A
authors.lastname: Abi-Hanna
authors.forename: Nancy
authors.initials: N
authors.lastname: Moore
authors.forename: Robert H
authors.initials: RH
authors.lastname: Yolken
mesh_terms: D001644:Bifidobacterium; D002675:Child, Preschool; D004311:Double-Blind Method; D004361:Drug Tolerance; D005260:Female; D006128:Growth; D006801:Humans; D007223:Infant; D007225:Infant Food; D007422:Intestines / Q000187:drug effects; D008297:Male; D019936:Probiotics / Q000008:administration & dosage / Q000494:pharmacology*