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Maternal nutrition, infants and children

Milk containing probiotic Lactobacillus rhamnosus GG and respiratory illness in children: a randomized, double-blind, placebo-controlled trial



To determine whether long-term daily consumption of milk containing probiotic Lactobacillus rhamnosus GG (GG) decreases respiratory illness in children.


A randomized, double-blind, placebo-controlled trial was conducted with 523 children aged 2–6 years attending day care centers in Finland. Subjects received either normal milk or the same milk with GG on three daily meals for 28 weeks. Daily recording of childrens’ symptoms was done by parents. Primary outcome data from 501 subjects were available for analysis, and data from 128 subjects were analyzed as completed cases in terms of recovery of GG in fecal samples.


Number of days with at least one respiratory symptom in all subjects was 5.03/month (95% confidence interval (CI): 4.92–5.15) in the GG group and 5.17/month (95% CI: 5.05–5.29) in the placebo group incidence rate ratio (IRR) 0.97; 95% CI: 0.94–1.00; P=0.098). In the completed cases, the figures were 4.71 days/month (95% CI: 4.52–4.90) in the GG group and 5.67 days/month (95% CI: 5.40–5.94) in the placebo group (IRR 0.83; 95% CI: 0.78–0.88; P<0.001).


Consumption of GG reduced the occurence of respiratory illness in children attending day care centers in the completed cases subgroup, but not in the total population. Thus, future clinical trials are warranted to clarify the association between fecal recovery of a probiotic and the symptom prevalence.

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We acknowledge the contribution of parents of children in the trial and day care center staff for their valuable assistance in the conduction of the study. We thank the field study team, including study coordinators, study nurses, study physicians, data management and other support staff for the practical arrangements of the study as well as Valio Ltd staff for the production and transportation of the study products. Soile Tynkkynen, Jaana Oksanen, Johanna Lahtinen, Outi Immonen and Katri Korpela are thanked for their assistance with the real-time quantitative PCR analysis. Professor Heikki Vapaatalo is thanked for sharing his expertise in planning and reporting the trial.

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Correspondence to R Korpela.

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Competing interests

The study was funded by Valio Ltd. MK, RAK and KH are employees of Valio Ltd. RK was employed by Valio Ltd at the time of the protocol development and execution of the intervention. The other authors declare no conflict of interest.

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Supplementary Information accompanies the paper on European Journal of Clinical Nutrition website

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Kumpu, M., Kekkonen, R., Kautiainen, H. et al. Milk containing probiotic Lactobacillus rhamnosus GG and respiratory illness in children: a randomized, double-blind, placebo-controlled trial. Eur J Clin Nutr 66, 1020–1023 (2012).

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  • probiotics
  • clinical trial
  • respiratory tract infections
  • communicable diseases

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