The effects of Lacticaseibacillus rhamnosus GG supplementation on gastrointestinal and respiratory outcomes: a systematic review and meta-analysis of randomized controlled trials

Abstract

The efficacy of Lacticaseibacillus rhamnosus GG (LGG) in reducing diarrhea duration in children is well established. However, its preventive potential and broader therapeutic applications beyond pediatric diarrhea have not been fully explored. A systematic review and meta-analysis were performedto investigate the efficacy of LGG supplementation on the risks of composite (including infections and symptoms) gastrointestinal (GI) and respiratory outcomes, as well as the duration of relevant symptoms. The protocol was pre-registered in the PROSPERO database (CRD42024539944). The PubMed, Web of Science, and Cochrane databases were searched for relevant articles. A random-effects model was applied to generate pooled relative risks (RRs) or weighted mean difference (WMD) estimates with 95% confidence intervals (CIs). Sixty-nine trials were included. LGG supplementation reduced the risk of composite GI outcomes (RR 0.88, 95% CI 0.81, 0.96; N=38), primarily through a reduction in diarrhea risk (RR 0.64, 95% CI 0.52, 0.77; N=24) and, to a lesser extent, taste disturbances (RR 0.40, 95% CI 0.22, 0.72; N=5). Respiratory outcome risk was also lower (RR 0.86, 95% CI 0.78, 0.94; N=23), mainly due to reduced respiratory infection risk (RR 0.87, 95% CI 0.79, 0.97; N=18). LGG shortened GI symptom duration (WMD -0.62, 95% CI -0.81, -0.44 days; N=33), mainly via reduced diarrhea duration (-0.83, 95% CI -1.06, -0.59 days; N=29). High heterogeneity was observed for the aforementioned outcomes, except taste disturbance. Prediction intervals supported consistent benefits for diarrhea outcomes but frequently crossed the null for others, indicating greater uncertainty. Effects were more consistent in children; evidence in adults was limited. Certainty was rated moderate for diarrhea outcomes and mostly low for others. LGG supplementation reduces diarrhea risk and duration in children with moderate certainty and consistent effects across trials. Other outcomes showed more variable results, reflecting limited or inconsistent evidence. These findings support LGG’s role in pediatric diarrhea management while underscoring the need for high-quality trials to clarify broader clinical applications.