Effect of Nutritional Factors on Mental Health Problems in Autism Spectrum Disorder: A Narrative Synthesis of Current...

Autism spectrum disorder (ASD) is frequently associated with co-occurring mental health challenges, such as anxiety and irritability, which severely impair quality of life. While nutritional research typically targets core ASD symptoms, this narrative synthesis specifically investigates the impact of nutritional interventions on these psychiatric comorbidities.

A structured literature search was performed across PubMed, Web of Science, and Scopus databases. Twenty-one peer-reviewed studies met the inclusion criteria, focusing on the relationship between dietary interventions/supplements and mental health outcomes in ASD populations.

Findings regarding gluten-free and casein-free (GFCF) diets remain inconclusive due to highly mixed results. While some trials involving vitamin D3, omega-3 fatty acids, and probiotics have reported improvements in anxiety and irritability, these findings are characterized by significant inconsistency. The overall strength of the evidence is limited by small sample sizes, short intervention durations, heterogeneous dosage protocols, and the use of diverse behavioral assessment scales.

Vitamin D3, omega-3 fatty acids, and probiotics show preliminary signals of benefit for managing certain mental health symptoms in ASD; however, current data are insufficient to confirm clinical effectiveness or to support the development of formal clinical guidelines. Future research requires large-scale, randomized, double-blind, placebo-controlled trials with standardized outcome measures and longer follow-up periods to clarify these inconsistent findings.