INTRODUCTION: Probiotics are live microorganisms that have a beneficial effect on the host.
OBJECTIVE: Our aim was to investigate whether consumption of probiotics would be able to reduce symptoms of respiratory tract infections during the winter season.
METHODS: Children aged 3 to 5 years were recruited and randomly assigned to 1 of 3 groups to receive placebo (n = 92), Lactobacillus acidophilus NCFM (NCFM) (n = 77), or a combination of L acidophilus NCFM and Bifidobacterium lactis Bi-07 (NCFM+Bi-07) (n = 79). Probiotics were consumed daily at a dose of 1010 colony-forming units for 6 months from November to April. The study was performed in Shanghai, China, and approved by the local authorities.
RESULTS: The incidence of fever was reduced by 63% in the NCFM+Bi-07 group and by 48% in the NCFM group. Cough was reduced by 54% in the NCFM+Bi-07 group and by 42% in the NCFM group. Runny nose was reduced by 44% in the NCFM+Bi-07 group and by 9% in the NCFM group; the latter result was not significant. Antibiotic use was reduced by 80% in the NCFM+Bi-07 group and by 68% in the NCFM group. Children in the placebo group had, on average, 6.5 days with symptoms, those in the NCFM group had 4.5 days with symptoms, and those in the NCFM+Bi-07 group had 3.4 days with symptoms.
CONCLUSIONS: Daily consumption of NCFM and Bi-07 and of NCFM alone significantly reduced the incidence and duration of respiratory tract infection symptoms in children. The combination of the 2 probiotics tended to perform better than the NCFM alone.