Effects of feeding an infant formula containing Lactobacillus GG on the colonization of the intestine: a dose-response study in healthy infants

J Clin Gastroenterol. 2005 Oct;39(9):786-90. doi: 10.1097/01.mcg.0000177245.53753.86.


Objectives: This study aimed to determine whether feeding Lactobacillus GG (LGG) at varying levels (10 to 10 cfu/day) would result in colonization, defined as > or =1,000 cfu of LGG per gram of stool in 3 of 5 samples collected during the feeding period.

Methods: Infants received unsupplemented formula during a 7-day baseline, 1 of 4 formulas containing 0 (control), 10 (low), 10 (medium), or 10 (high) cfu of LGG per day during a 2-week test, and unsupplemented formula during a 2-week follow-up. Baseline, test, and follow-up stool samples were evaluated for levels of viable LGG.

Results: During test, supplemented infants were colonized, compared with control (P < 0.05). Median stool counts of LGG (log10 cfu/g) in colonized infants were 5.24 (low), 6.05 (medium), and 5.97 (high). LGG persisted in the stools for 7 to 14 days after discontinuing LGG. No differences were observed among groups in stool consistency, flatulence, fussiness, or adverse events.

Conclusion: A 2-week oral administration of 10 to 10 cfu/day LGG was well tolerated; all levels successfully colonized the intestinal tract of healthy, term infants.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colony Count, Microbial
  • Double-Blind Method
  • Feces / chemistry
  • Feces / microbiology
  • Female
  • Follow-Up Studies
  • Humans
  • Infant Formula / administration & dosage*
  • Infant, Newborn
  • Intestines / microbiology*
  • Lactobacillus / growth & development*
  • Lactobacillus / isolation & purification
  • Male
  • Reference Values