Micronutrient deficiencies in children with autism spectrum disorders compared to typically developing children – A scoping review

Background

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that may be influenced by various factors, including nutritional status. This scoping review, adhering to PRISMA-ScR guidelines, aims to systematically explore and synthesize the existing literature on micronutrient (vitamins, minerals and trace elements) deficiencies in children with ASD and how they may differ from the general population of typically developing children.

Methods

A comprehensive search strategy was employed across multiple databases, selecting studies that quantitatively assessed micronutrient levels in children with ASD and control groups. The inclusion of 34 full-text publications from 17 countries provided a geographically diverse sample, ensuring a broad overview of the field.

Results

The findings present a complex picture of micronutrient levels in children with ASD. A recurrent observation was lower vitamin D levels in children with ASD across multiple studies, while results for other vitamins, such as vitamins A and E, and minerals like iron (ferritin), iodine, and zinc were mixed and contradictory. The heterogeneity in study methodologies, participant characteristics, and controls for confounding factors, such as supplementation, were noted as significant variables influencing outcomes.

Conclusion

This scoping review accentuates the crucial need for standardized methodologies in future research to explore the underlying mechanisms of altered micronutrient levels in children with ASD and determine potential therapeutic implications. Emphasis on careful consideration of external variables, such as dietary habits and supplementation, is imperative to draw valid, reproducible conclusions in subsequent studies.