The role of intestinal flora in autism and nutritional approaches

e-mail: aslimelike01@gmail.com ABSTRACT Autism spectrum disorder (ASD) is a social behavior disorder and awareness on ASD has been increasing nowadays. Social deficiencies and repetitive movements constitute the symptoms of ASD occurring in childhood. As there is no biological marker in autism, parental and clinician approaches are based on diagnosis. Genetic and environmental factors play a role in autism, and its prevalence has been increasing in recent years. The process and amount of exposure to environmental factors create differences in the cause of autism. Although it is unclear yet whether autism is a cause or result, impaired intestinal flora is among the symptoms of autism. Factors such as nutrition approaches and perinatal factors have been thought to play a role in intestinal flora dysbiosis. Metabolites that cross the blood-brain barrier in the intestinal flora dysbiosis can cause morphological changes in the hippocampus in the brain. Various dietary approaches and fecal microbiota transplantation have become candidates for autism treatment methods to improve the deteriorated flora. In this review, we discuss the effects of therapeutic nutritional approaches and fecal transplantation by examining the relationship between ASD and