A Systematic Review of the Role of Prebiotics and Probiotics in Autism Spectrum Disorders

Area of Science:

• Neuroscience
• Gastroenterology
• Microbiome research

Background:

• Autism spectrum disorder (ASD) is a complex developmental condition affecting social and communication behaviors, with an incompletely understood pathogenesis.
• Individuals with ASD frequently experience gastrointestinal (GI) complaints, prompting interest in gut-related interventions.
• Anecdotal evidence suggests probiotics may improve GI and behavioral symptoms in children with ASD, but systematic reviews are lacking.

Purpose of the Study:

• To systematically review the existing clinical evidence on the efficacy of prebiotics and probiotics in managing symptoms associated with autism spectrum disorder.
• To evaluate the impact of prebiotics and probiotics on both gastrointestinal and behavioral manifestations in children with ASD.

Main Methods:

• A systematic literature search was performed across major databases (PubMed, EMBASE, Medline, Clinicaltrials.gov, Google Scholar) using keywords related to prebiotics, probiotics, microbiota, gut, autism, social, and ASD.
• Inclusion criteria focused on original clinical trials published in English between January 1988 and February 2019.
• Eight clinical trials were reviewed, comprising two on prebiotics/diet exclusion and six on probiotic supplementation.

Main Results:

• Prebiotics alone showed limited improvement in GI symptoms. However, combined with a gluten- and casein-free diet, prebiotics significantly reduced anti-social behavior scores.
• Probiotic supplementation demonstrated limited evidence for alleviating GI or behavioral symptoms in children with ASD.
• The two available double-blind, randomized, placebo-controlled trials found no significant differences in GI symptoms or behavior between probiotic and placebo groups.

Conclusions:

• Prebiotics and probiotics exhibit limited efficacy in managing GI or behavioral symptoms in children with ASD, despite promising preclinical data.
• A lack of standardized probiotic regimens, including varied strains, concentrations, and treatment durations, complicates treatment evaluation.
• Further research is needed to clarify the potential role and optimal use of gut-targeted interventions in ASD management.