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Randomized Controlled Trial
. 2020 Jul 3;12(7):1989.
doi: 10.3390/nu12071989.

A Double-Blind, Randomized, Placebo-Controlled Trial of Heat-Killed Pediococcus acidilactici K15 for Prevention of Respiratory Tract Infections among Preschool Children

Haruka Hishiki  1 , Tadaomi Kawashima  2 , Noriko M Tsuji  3 , Naho Ikari  2 , Ryo Takemura  4   5 , Hiroshi Kido  6 , Naoki Shimojo  1   7
Affiliations
Randomized Controlled Trial

A Double-Blind, Randomized, Placebo-Controlled Trial of Heat-Killed Pediococcus acidilactici K15 for Prevention of Respiratory Tract Infections among Preschool Children

Haruka Hishiki et al. Nutrients. .

Abstract

Although some probiotic bacteria have been reported to prevent infections in children, there are few well-designed double-blind studies. Here we evaluated the effects of a probiotic strain of lactic acid bacteria (LAB), Pediococcus acidilactici K15, on viral respiratory tract infections in preschool children. A four-month, randomized, double-blind, placebo-controlled study was performed in 172 healthy children aged 3 to 6 years. Subjects were administered dextrin alone or dextrin including heat-killed K15 (5 × 1010 bacteria). The number of febrile days was the primary outcome. The number of absent days from preschools and the influenza incidence were secondary outcomes. Secretory IgA (sIgA) concentrations in saliva were measured as an exploratory outcome. The primary and secondary outcomes were not significantly different between both groups. Analyses in children with little intake of fermented foods including LAB showed that the duration of a fever significantly decreased by K15 intake. The salivary sIgA level in the K15 group was maintained significantly higher than it was in the placebo group. The effects of K15 on preventing viral respiratory tract infections were not observed without the restriction of fermented foods intake. However, K15 supported anti-infectious immune systems in children who took less fermented foods and the maintenance of salivary sIgA levels in all subjects.

Keywords: Pediococcus acidilactici K15; double-blind study; febrile days; preschool children; respiratory tract infections; safety; secretory IgA.

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Conflict of interest statement

T.K. and N.I. are employed by Kikkoman Corporation, which is a food manufacturing company, however, they had no involvement in designing this clinical trial, nor in analyzing data. The authors declare no other conflict of interest.

Figures

Figure 1
Figure 1
Flowchart of the study recruitment.
See this image and copyright information in PMC

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