Researchers performed a case-controlled cross-sectional analysis on 122 autism spectrum disorder (ASD) children, to assess their vitamin D status compared to controls and the relationship between vitamin D deficiency and the severity of autism. They also conducted an open trial of vitamin D supplementation in ASD children. Results showed 57% of the patients in the study had vitamin D deficiency and 30% had vitamin D insufficiency. Mean 25(OH)D levels in patients with severe autism were significantly lower than those in patients with mild/moderate autism. 25(OH)D levels had significant negative correlations with Childhood Autism Rating Scale (CARS) scores. Of the ASD group, 83 patients with low serum 25(OH)D levels (<30 ng/ml) completed the open label trial. They received 300 IU/Kg/day of vitamin D3, not to exceed 5000 IU/day, for 3 months. 67 (80.72%) had significantly improved outcome, which was mainly in the sections of the CARS and aberrant behavior checklist subscales that measure behavior, stereotypy, eye contact, and attention span.
Khaled Saad, et al. Vitamin D status in autism spectrum disorders and the efficacy of vitamin D supplementation in autistic children. Nutritional Neuroscience. 2015