Insufficient levels of vitamin D have been associated with the risk of autism spectrum disorder (ASD) as well as the severity of ASD symptoms
It has been suggested that vitamin D acts as a neuroactive steroid, influencing neuronal differentiation, axon connectivity, and brain structure and function.
Vitamin D also regulates gene expression, upregulates DNA repair genes, modulates immune responses and controls inflammation.
As a follow-up to an open-label study of vitamin D in children with ASD, Saad, Abdel-Rahman and colleagues conducted a randomised, controlled trial to evaluate the effects of vitamin D supplementation on the core symptoms of ASD in children recruited from five private treatment centers in Egypt.
A total of 109 children (age range 3-10 years), with a boy to girl ratio of 3.5:1, completed this study.
Children were randomised to a placebo or vitamin D3 (300IU/kg/d, not to exceed 5000IU/d) for 4 months.
Autism severity and social maturity were assessed with the Childhood Autism Rating Scale (CARS), Aberrant Behaviour Checklist (ABC), Autism Treatment Evaluation Checklist (ATEC) and the Social Responsiveness Scale (SRS).
There were no significant differences between groups in baseline scores of autism severity.
After 4 months, scores on all 4 of the scales and checklists (CARS, ABC, ATEC, SRS) were significantly improved when compared with the placebo.
In the vitamin D group, improvements were observed in relating to people, emotional response, imitation, body use, object use, adaptation to change, listening response, visual response, general autistic impression, irritability, hyperactivity, social withdrawal, stereotypic behaviour, inappropriate speech, autistic mannerisms, repetitive hand movements, creation of noises, jumping, restricted interests, sociability and cognitive awareness.
No significant changes were observed in communication parameters. Vitamin D supplementation was well tolerated, with few adverse effects.
Pharmacological treatments of ASD primarily reduce symptoms associated with ASD, such as anxiety or hyperactivity, rather than the core symptoms of ASD.
Results of this first randomised, double-blind, placebo-controlled trial of vitamin D in children with ASD suggest that vitamin D may be an effective intervention to improve the core manifestations of ASD.