The Effects of Probiotics and Prebiotics on Gastrointestinal and Behavioural Symptoms in Autism Spectrum Disorder

Background: Autism Spectrum Disorders (ASDs) are a group of prevalent neuropsychiatric disorders. They present a complex and unknown etiology, which in most cases includes significant peripheral alterations outside the brain such as in the composition of gut microbiota. Because the gut microbiota is involved in modulating the gut-brain axis, several studies have suggested that the microbiome in the gut can modify metabolites which are able to cross the blood-brain barrier and modulate brain function. Methods: We reviewed the current evidence regarding microbiota alterations in patients with ASD and the effects of the administration of probiotics and prebiotics in these patients, both in terms of gastrointestinal and behavioural symptoms. Results: Administration of a probiotic formulation containing different strains of Lactobacillus (L. acidophilus, L. rhamnosus, and others) and Bifidobacteria had beneficial effects upon these aforementioned symptoms and their use is recommended in a subgroup of ASD patients that present gastrointestinal disturbances. Nonetheless, the types of gastrointestinal disturbances that most benefit from such interventions remain to be elucidated in order to personalize the medical approaches. Conclusion: Recent clinical studies have shown that probiotic treatments can regulate the gut microbiota and may result in improvements in some behavioral abnormalities associated with ASD. Trials using prebiotic fibers or synbiotics preparations are still lacking and necessary in order to deep in such therapeutic strategies in ASD with comorbid gastrointestinal disrturbances.