Postnatal probiotics administration does not prevent asthma in children, but using prebiotics or synbiotics may be the effective potential strategies to decrease the frequency of asthma in high-risk children - a meta-analysis of clinical trials.

Background: The role of probiotics, prebiotics, and synbiotics in preventing asthma and other allergic diseases has been widely explored via many randomized controlled trials. However, the results on the effect of their supplementation during infancy to the incidence of allergic rhinitis or asthma, are conflicting.The study was designed to bring to light the potential effects of pro-, pre-, and synbiotics supplementation in early childhood with regard to the future occurrence of allergic diseases.

Method: The results of randomized controlled trials were searched for in several medical data bases. The study protocol was prepared in accordance with PRISMA guidelines and applied a Revised Cochrane risk-of-bias tool for randomized trials. Two writers were designed to perform studies selection.

Results: Eleven randomized controlled trials, among 1659 children (525 in the probiotic group, 342 in prebiotic group, 128 in synbiotic group and 833 in control groups) were analyzed. There was no difference in asthma risk development between the groups that received probiotics or placebo. We observed lower risk of asthma in children receiving prebiotic and synbiotic than in control groups.

Conclusion: The current study indicates that probiotics supplementation in the first months after birth does not decrease the risk of asthma development in the first years of life in high-risk children, although prebiotics and synbiotics may be the potential preventive factors that reduce the incidence of asthma in children.