Autism: Vitamin D Helps Improve Behavior
Autism and vitamin D: here’s what connects them and how it improves behavior
Vitamin D can influence serotonin levels in the brain and modify abnormal behaviors in children with autism. More specifically, adequate vitamin D levels appear necessary to stimulate production of this important hormone that regulates brain function, structure, and social behavior.
This emerges from a study published in The FASEB Journal, conducted at the Children's Hospital Oakland Research Institute in California (USA), aiming to reveal the link between serotonin, vitamin D, and autistic disorder.
Autism, serotonin, and vitamin D
Serotonin, also known as the "feel-good hormone," is a neurotransmitter produced in the brain and other tissues from the amino acid tryptophan. Several studies in recent years have identified a relationship between serotonin deficiency and autism, a neuropsychiatric disorder characterized by repetitive and stereotyped behaviors and impairments in communication and social relationships. Previous research has found a link between autism and vitamin D deficiency, a molecule mainly known for regulating calcium and phosphorus absorption and storage. Until now, the mechanism linking vitamin D, serotonin, and autism symptoms had not been elucidated.
Discoveries of the new study
Researchers found that vitamin D can activate the gene producing the enzyme TPH2 (tryptophan hydroxylase 2), necessary to convert the amino acid tryptophan into serotonin in the central nervous system. Conversely, vitamin D can deactivate the gene for the enzyme TPH1, which, like TPH2, produces serotonin in the gut and other tissues where, if in excess, it promotes inflammation.
The opposite effects of vitamin D on these two genes may explain some typical autism conditions, including elevated blood serotonin levels compared to the nervous system and consequent deficits in brain development. Low vitamin D levels during fetal and neonatal development could cause insufficient TPH2 activity with serious structural and functional brain consequences.
This hypothesis suggests the importance of adequate vitamin D intake during pregnancy, as well as vitamin D and tryptophan during early childhood. Researchers also discovered that oxytocin and vasopressin, two other brain hormones influencing social behavior, are stimulated by vitamin D presence.
Vitamin D to improve autism symptoms
Although further studies are needed, researchers hypothesize that supplementation with vitamin D, along with Omega-3 and tryptophan, could help prevent or improve some typical autism behaviors without risk of side effects.
In this regard, they also pointed out that recommended vitamin D levels in guidelines refer to concentrations necessary to ensure proper bone health (30 ng/mL), but may not be sufficient to guarantee other functions in tissues such as the nervous system.
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Source: Rhonda P. Patrick and Bruce N. Ames “Vitamin D hormone regulates serotonin synthesis. Part 1: relevance for autism” The FASEB Journal, 2014; DOI: 10.1096/fj.13-246546.
