Autism symptoms – such as hyperactivity, social withdrawal, and others – improved significantly following vitamin D3 supplementation.  Children 3-10 took the supplement for four months.  The daily dosage varied based on a child’s weight.

Source: “Randomised Controlled Trial of Vitamin D Supplementation in Children with Autism Spectrum Disorder” by K.Saad et al., Journal of Child Psychology and Psychiatry, 11/21/16.