Effect of probiotic fermented dairy products on incidence of respiratory tract infections: A systematic review and meta-analysis of randomized clinical trials

Previous studies have suggested that the consumption of probiotic fermented dairy products (PFDP) may have a protective effect on respiratory tract infections (RTls). However, the results of the studies are inconclusive. We aimed to systematically investigate the effect of PFDP on RTIs by performing a meta-analysis of randomized controlled trials (RCTs). A total of 22 RCTs, with a total sample size of 10,190 participants, were included in this meta-analysis. Compared with placebo, consumption of PFDP had a significant protective effect against RTIs in the overall analysis.