Does the Use of Probiotics Reduce the Incidence of Upper Respiratory Tract Infections (URTIs) in Adult Athletes?

OBJECTIVE: The objective of this selective EBM review is to determine whether or not probiotics reduce the incidence of upper respiratory tract infections (URTIs) in adult athletes. STUDY DESIGN: A systematic review of three placebo-controlled randomized trials. The articles were published in peer reviewed journals between 2008 and 2018 in the English language. DATA SOURCES: Three placebo-controlled, single- or double-blinded, randomized trials comparing the efficacy of placebo vs. probiotics in reducing URTI episodes in athletes over the age of 18 years old. The articles were found using PubMed and Cochrane via key words. OUTCOME MEASURED: The outcome measured compared placebo to probiotics by the number of URTI episodes determined by patient-reported daily symptom logs confirmed by a physician when possible. RESULTS: One study showed a significant difference in probiotics reducing the incidence of URTIs (Strasser B, Geiger D, Schauer M, et al. Nutrients. 2016;8(11):10.3390/nu8110752. doi: E752) while the studies by Haywood et al (J Sci Med Sport. 2014;17(4):356-360. doi: 10.1016/j.jsams.2013.08.004) and Cox et al (Br J Sports Med. 2010;44(4):222-226. doi: 10.1136/bjsm.2007.044628) were determined to have an insignificant difference. CONCLUSION: The answer to whether probiotics reduce the incidence of URTIs in adult athletes is inconclusive in the analysis of the selected three studies