Effects of probiotic supplementation on respiratory infection and immune function in athletes. - GreenMedInfo Summary

OBJECTIVE: The aim of this study was to evaluate the effectiveness of probiotic supplementation on upper tract respiratory infection and inflammatory markers in elite athletes.

DATA SOURCES: We identified sources by searching the PubMed, EBSCO host, Scopus, and Web of Science databases using the following search terms:"probiotic"OR"probiotics"AND"exercise"OR"sport"OR"athletes"AND"URTI"OR"respiratory infection"OR"upper respiratory tract infections"OR"inflammation"OR"inflammatory OR"cytokines".

STUDY SELECTION: We screened the title and abstracts of 2498 articles using our inclusion critieria. A total of 14 articles were selected for further analysis.

DATA EXTRACTION: Data from the included studies were extracted by 2 independent reviewers. These data included the study design, participant characteristics, inclusion and exclusion, intervention characteristics, outcome measures, and the main results of the study.

DATA SYNTHESIS: The meta-analysis did not show any significant effect of probiotic supplementation on the number of days of illness or the mean number and duration of URTI episodes, but there was a significant effect of probiotic supplementation on total symptom severity score (-0.65, 95% CI: -1.05; -0.25, p = 0.02). Lower levels of IL-6 (-2.52 pg/ml, 95% CI: -4.12, -0.51, p = 0.001) and TNF-α (-2.31 pg/ml, 95% CI: -4.12, -0.51, p = 0.008) were also reported after supplementation.

CONCLUSIONS: This meta-analysis provides evidence that probiotic supplementation, especially among professional athletes, is an effective way to decrease the total URTI symptom severity score. Additionally, probiotic supplementation may decrease TNF-α and IL-6 levels. There is a need for more studies with larger groups to better estimate this effect. It is necessary to determine the best timing, duration, composition and dose of such supplementation.