Microbiota intestinal e transtorno do espectro autista: uma investigação da literatura nos últimos dez anos.

Abstract

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by difficulties in communication, social interaction, and repetitive and restricted behaviors, with increasing global prevalence. Recently, the intestinal microbiota has been investigated as a possible factor involved in the etiology and manifestation of ASD, due to its influence on the gut-brain axis. Therefore, this study aimed to investigate the relationship between intestinal microbiota and ASD in the scientific literature of the last decade, in children and adolescents aged 2 to 8 years. The methodology consisted of an integrative literature review, with a survey in databases such as PubMed, SciELO, and Google Academic, covering articles published between 2005 and 2015. The PICO strategy was used to create the guiding research question and the PRISMA model was used to systematize and organize the articles in the results of this research. Case-control studies and randomized clinical trials were included, following previously established inclusion and exclusion criteria. The results showed significant changes in the microbiota of children with ASD, such as an increase in pathogenic bacteria and a reduction in beneficial species, in addition to imbalances in the production of short-chain fatty acids, alpha-linolenic acid and tryptophan. Dietary interventions, such as the gluten-free and casein-free diet (GCA) and the ketogenic diet, as well as probiotic supplementation, demonstrated improvements in gastrointestinal and behavioral symptoms in some studies, although with heterogeneous results. Therefore, it is concluded that intestinal dysbiosis is correlated with ASD, and that interventions aimed at modulating the microbiota represent a promising approach. However, additional studies are needed, with greater methodological rigor, larger samples, prolonged follow-up, methodological standardization, a wash-out period with a controlled diet before interventions and the use of uniform assessment instruments, in order to generate reliable and representative results.