Use of probiotics as a complementary therapy in the management of autism

Abstract

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by difficulties in social communication, interaction, and the presence of repetitive behavioral patterns. Recent evidence suggests that probiotics, by modulating the gut-brain axis, may improve both gastrointestinal and behavioral symptoms. Materials and Methods: A systematic review was conducted following PRISMA guidelines. Databases searched included PubMed, SciELO, ScienceDirect, and Google Scholar for studies published between 2021 and 2025. Ten relevant articles were selected (randomized clinical trials, systematic reviews, and meta-analyses), and their methodological quality was assessed using the PEDro and AMSTAR-2 scales. Results: The analysis of systematic reviews and meta-analyses showed mild to moderate improvements in gastrointestinal symptoms (MD = -0.59; p < 0.05) and behavioral outcomes, particularly in irritability, social communication, and adaptive behavior (pooled SMD = -0.19 to -0.38; p < 0.05). However, high heterogeneity across studies, differences in treatment duration, probiotic strains, dosages, and clinical scales limit generalizability. Discussion: Recent studies agree that probiotics may improve gastrointestinal and behavioral symptoms in children with ASD, highlighting the role of the gut-brain axis. Lactobacillus plantarum PS128 has shown consistent positive effects. Nevertheless, methodological limitations remain, including heterogeneity in strains, doses, and intervention duration. Conclusion: Probiotics represent a promising complementary therapeutic option for ASD. However, further well-designed, controlled, and standardized clinical trials are needed to validate their clinical use and establish evidence-based recommendations.