The importance of probiotics for children

By Alan R. Gaby, M.D.

Probiotics are “friendly” microorganisms (typically bacteria or yeasts) that can live in the gastrointestinal tract or on other mucosal surfaces and have beneficial effects on human physiology and health. Probiotic organisms are believed to work in part by enhancing digestion and immune function by competing with pathogenic microorganisms for binding sites on mucosal surfaces.

Numerous studies have found that probiotics can moderate occasional diarrhea in children. In one double-blind study, 200 children were randomly assigned to receive 250 mg per day of Saccharomyces boulardii for five days. In another double-blind trial, 269 children were randomly assigned to receive 250 mg of S. boulardiitwice per day.1 In both trials, S. boulardii provided statistically significant support for healthy stool transit time.

The positive effects of probiotics in children are not limited to the gastrointestinal tract. Various probiotics have also been used to support immune health. In one study, 571 healthy children (aged 1-6 years) attending daycare centers were randomly assigned to receive milk with or without Lactobacillus GG for seven months over the winter. Results suggested that L. GG provided statistically significant support for respiratory health.2In another study, 201 healthy infants attending daycare centers were randomly assigned to receive, in double-blind fashion, a formula supplemented with B. lactisL. reuteri, or no probiotics for 12 weeks. Probiotic supplementation indicated statistically significant support for overall health, immune function and GI comfort.3

Supplementation with select probiotic strains have also been found to promote dental health in children. In one study, 594 children were randomly assigned to receive milk that did or did not contain L. GG. Researchers reported that probiotic supplementation provided statistically significant support for dental health; the beneficial effect was most pronounced in children three to four years of age. L. GG may work in part by moderating the growth of Streptococcus mutans.4 The strain Streptococcus salivarius K12 has been shown to persist in the oral cavity for as long as three weeks after oral administration as a lozenge5, which raises the possibility that this strain may be able to promote dental health by competing with other oral bacteria. In addition, S. salivarius K12 has been reported to help protect ear and throat health.6

Based on the available evidence, probiotic supplementation in children appears to be a worthwhile strategy to help promote overall good health. A wide range of probiotic strains have been investigated in multiple clinical trials and results suggest that the efficacy of different strains may differ depending on the health condition. Additional research is needed to further explore these specific benefits.


  1. Kotowska M, Albrecht P, Szajewska H. Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea in children: a randomized double-blind placebo-controlled trial. Aliment Pharmacol Ther 2005;21:583-590.
  2. Hatakka K, Savilahti E, Ponka A, et al. Effect of long term consumption of probiotic milk on infections in children attending day care centres: double-blind, randomised trial. BMJ 2001;322:1327-1329.
  3. Weizman Z, Asli G, Alsheikh A. Effect of a probiotic infant formula on infections in child care centers: comparison of two probiotic agents. Pediatrics 2005;115:5-9.
  4. Nase L, Hatakka K, Savilahti E, et al. Effect of long-term consumption of a probiotic bacterium, Lactobacillus rhamnosus GG, in milk on dental caries and caries risk in children. Caries Res 2001;35:412-420.
  5. Horz HP, Meinelt A, Houben B, Conrads G. Distribution and persistence of probiotic Streptococcus salivarius K12 in the human oral cavity as determined by real-time quantitative polymerase chain reaction. Oral Microbiol Immunol 2007;22:126-30.
  6. Cosseau , Devine DA, Dullaghan E, et al. The commensal Streptococcus salivarius K12 downregulates the innate immune responses of human epithelial cells and promotes host-microbe homeostasis. Infect Immun 2008;76:4163-4175.