Probiotics for Prevention or Treatment of Asthma

Abstract

PURPOSE: Probiotics are live organisms which exert a beneficial effect in the prevention as well as treatment of allergic diseases through modification of immune system of host via gut ecosystem. Intestinal microbiota differs in infants who later develop allergic diseases, and feeding probiotics to infants at risk has been shown to reduce their rate of developing eczema. This has prompted studies of feeding probiotics in prevention as well as treatment of respiratory allergies including asthma. METHODS: A systematic search of published literature was done. Randomized Controlled Trials (RCTs) (Quality score ≥ 3) of probiotics in prevention or treatment of asthma were included. A pre‐defined set of outcome measures were assessed. Weighted mean difference (WMD) with 95% confidence interval (CI) was calculated using RevMan (version 4.2.10). RESULTS: Three eligible studies (Australia =1, Finland =1, Sweden =1) evaluated preventive role of probiotics and enrolled 617 term or near term infants at high risk of allergy or food hypersensitivity. There was no significant difference in asthma incidence, [RR 0.83 (95% CI 0.38, 1.8; p = 0.6)] or prevalence in childhood, [RR 3.06 (95% CI 0.33, 28.46; p = 0.3)]. On subgroup analysis, no strain specific effects of probiotics were found. Three eligible studies (Italy =1, Finland =1, USA =1) enrolled 141 subjects for evaluating role of probiotics in treatment of mild to moderate asthma. Probiotic intake was associated with longer time free from episodes of asthma, [WMD 0.8 (95% CI 0.62, 0.98; p < 0.00001)], though no difference was found in the mean duration of an episode, [WMD ‐0.47(95% CI ‐1.47 to 0.53)]. One study that reported quality of life score, found no change in the score. No serious adverse events were reported. CONCLUSION: There is no role of probiotics in prevention, though they may have role in treatment of asthma. CLINICAL IMPLICATIONS: Clinical trials of good methodologic quality and adequatesample size evaluating clinically relevant outcomes are needed before probiotics are recommended for use in asthma.