Effects of Nutritional Interventions on Autism Spectrum Disorder Symptomatology: A Systematic Literature Review

Abstract

Introduction: Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by persistent alterations in communication, behavior, and social interaction. Although its etiology is multifactorial and complex, there is growing scientific interest in understanding the role of nutrition as a complementary intervention capable of modulating behavioral and gastrointestinal symptoms commonly associated with ASD.

Objectives: To evaluate the effect of nutritional interventions on the symptomatology of individuals diagnosed with Autism Spectrum Disorder.

Materials and Methods: A literature search was conducted in PubMed, Scopus, and Web of Science. Eleven studies investigating nutritional interventions in children and adolescents with ASD were included, encompassing both dietary supplementation and dietary modifications.

Results: Most studies, 72,73% (n = 8), examined the effects of nutritional supplements such as vitamin D, omega-3, folinic acid, sulforaphane, prebiotics, and probiotics. Dietary interventions — including low-FODMAP diets, gluten-free diets, and gluten-free and/or casein-free diets — were evaluated in 27,27% (n = 3) of the articles. The low-FODMAP diet demonstrated significant improvements in gastrointestinal symptoms and some behavioral outcomes, whereas gluten-free and/or casein-free diets produced inconsistent results. Supplement-based interventions showed reductions in irritability and hyperactivity, improvements in social interaction and communication, and benefits for intestinal health, although findings varied across studies.

Conclusions: Nutritional interventions may help improve ASD symptoms, but limited and heterogeneous studies mean more research is needed to confirm their effectiveness and identify who benefits most.