Hanım Şeyma TOPUZ, Hasan ÖNAL
Comprehensive Medicine - 2026;18(2):219-223
Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by difficulties in social communication and is defined as a neurodevelopmental disorder. Gastrointestinal (GI) comorbidities, reported at markedly higher rates than in neurotypical populations, are increasingly recognized as clinically relevant modulators of core and associated ASD symptoms. These disturbances-often manifesting as constipation, diarrhea, abdominal pain, and gastroesophageal reflux-are frequently accompanied by pronounced feeding selectivity, sensory hypersensitivity, and nutrient deficiencies. Emerging evidence implicates gut microbiota dysbiosis in ASD pathophysiology, acting through immune, metabolic, and neurochemical pathways within the gut-brain axis. Alterations in microbial diversity and taxa abundance, including depletion of fiber-associated genera and enrichment of pro-inflammatory species, may contribute to both GI and behavioral phenotypes. Although dietary interventions such as gluten-free/casein-free, ketogenic, specific carbohydrate diets, and the Mediterranean diet have been proposed to restore microbial homeostasis, clinical evidence remains limited and inconsistent. Fecal microbiota transplantation (FMT) is an innovative treatment approach that preliminary open-label studies suggest may provide lasting improvements in GI and neurobehavioral areas. However, its long-term safety, efficacy, and mechanisms should be confirmed through rigorously designed randomized controlled trials. Future research should adopt multi-omics and longitudinal approaches to delineate causal relationships between microbiota alterations and neurodevelopmental outcomes, enabling the development of targeted microbiome-based and personalized nutritional strategies. Such precision interventions hold promise for addressing the unmet clinical needs of individuals with ASD.
