Autism and vitamin D evidence - Cannell

Created February 2016

Vitamin-D and Autism Spectrum Disorder (ASD): prevention and treatment. , John Cannell

Context. Autism Spectrum Disorder [ASD], a common neurodevelopmental disorder characterized by impaired communication, and repetitive behaviours, diagnosed in 1 in every 64 eight-year-old American children, has recently shown dramatically increased incidence, possibly reflecting increased surveillance, over-diagnosis, or being a true increase in incidence.

Evidence acquisition , from the relevant peer-reviewed literature [1960's-2016 (PubMed)].

Evidence synthesis . Data collation on hypovitaminosis-D effects on neural function, and of effects of high-dosage vitamin D, including two randomized controlled trials (RCT) in autistic children.

Mechanisms. Possible mechanisms of action of vitamin D in preventing and treating ASD are well known, as recently [and repeatedly] reviewed, reducing risk or severity through anti-inflammatory effects, DNA repair mechanisms, anti-autoimmune effects, raising seizure threshold, increasing T-regulatory cells, protecting mitochondria, and up-regulating glutathione, which scavenges oxidative by-products and clears heavy metals [by chelation].

Epidemiological data . Recent meta-analysis [11 cross-sectional studies] reported vitamin D deficiency was much more common in children with ASD than in controls.[ Wang T, Shan L, Du L, Feng J, Xu Z, Staal WG, Jia F. Serum concentration of 25-hydroxyvitamin D in autism spectrum disorder: a systematic review and meta-analysis. Eur Child Adolesc Psychiatry. 2015 Oct 29

] Another study found that new-borns who later developed autism had lower vitamin D levels at birth than their healthy siblings, suggesting that the vitamin D system is involved in ASD genetics.[ Fernell E, Bejerot S, Westerlund J, Miniscalco C, Simila H, Eyles D, Gillberg C, Humble MB. Autism spectrum disorder and low vitamin D at birth: a sibling control study. Fernell E, Bejerot S, Westerlund J, Miniscalco C, Simila H, Eyles D, Gillberg C, Humble MB. Mol Autism. 2015 Jan 14;6:3.]

Human interventional studies Only two RCTs [of high-dose vitamin D (300 IU/kg/day) are reported; both finding significant improvement in ~75% of supplemented ASD children.[ Feng J, Shan L, Du L, Wang B, Li H, Wang W, Wang T, Dong H, Yue X, Xu Z, Staal WG, Jia F. Clinical improvement following vitamin D3 supplementation in Autism Spectrum Disorder. Nutr Neurosci. 2016 Jan 18.], [ Randomized-Controlled Trial of Vitamin D Supplementation in Children with Autism Spectrum Disorder: (In submission) Clinical Trial. Trial registration number: UMIN-CTR Study Design: trial Number: UMIN000020281.]

An open study of infants born to mothers who already had one child with ASD, found vitamin D given to pregnant women and young children reduced subsequent ASD incidence to 5% instead of the 20% consistently reported for such infants in the literature.[ Stubbs G, Henley K, Green J. Autism: Will vitamin D supplementation during pregnancy and early childhood reduce the recurrence rate of autism in newborn siblings? Med Hypotheses. 2016 Mar;88:74-8.]

Conclusions.

High-dose vitamin D administration appears to improve core features of ASD, through well described actions of vitamin D on the central nervous system. Future RCTs of vitamin D in ASD may fail if lower doses are used, if subjects are sufficient at baseline, if placebo controls are treated, if pre/post RCT 25(OH)D levels are not done, and if ASD rating scales are not used.

Overall, therefore, we recommend avoidance of hypovitaminosis D in pregnancy and childhood by supplementing all pregnant women, infants and toddlers with adequate amounts of vitamin D [see Section XX].

See also Vitamin D Life

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Tags: Autism