Haidut has made several posts previously on autism, including on the potential therapeutic role of vitamin D and the potential causative role of serotonin.
Vitamin D May Be A Viable Therapy For Autism (human Study)
Children Conceived In Winter Have Much Higher Risk Of Autism
Gut Dysbiosis May Cause Autism Through Cortisol And Serotonin
Children With Autism Have High Serotonin Levels
Serotonin Causes Autism; Blocking It May Treat Autism
Some evidence below that deficiencies of vitamin A may be involved as well and that supplementation of vitamin A can reduce serotonin levels and improve autism symptoms.
Update: information on dose below
Brain Res Bull. 2017 Nov 6;137:35-40. doi: 10.1016/j.brainresbull.2017.11.001. [Epub ahead of print]
Vitamin A improves the symptoms of autism spectrum disorders and decreases 5-hydroxytryptamine (5-HT): A pilot study.
Guo M1, Zhu J1, Yang T1, Lai X1, Liu X1, Liu J1, Chen J1, Li T2.
Autism spectrum disorders (ASD) are complicated neurodevelopmental disorders. Many studies have demonstrated that children with autism have multiple nutritional deficiencies and increased serum 5-hydroxytryptamine (5-HT) levels. In our previous study, 77.9% of autistic children were found to have vitamin A deficiency, and the concentration of vitamin A was negatively associated with the CARS score. In the present study, we sought to test whether vitamin A supplementation could improve autistic symptoms and decrease serum 5-HT levels. The DSM-V criteria and CARS score were used for symptom description and symptom assessment of the patients, respectively, before and after vitamin A supplementation (VAS). Serum retinol and 5-HT levels, mRNA levels of RAR α, β, and γ and TpH 1 expression were detected in autistic children before and after VAS and in normal children. Serum retinol levels in children with ASD were significantly lower than in control children. Serum 5-HT levels in children with ASD were higher than in control children, which were correlated with symptom severity of children with autism. After VA supplementation, the children with ASD exhibited significant improvement in autism symptoms. Serum retinol concentrations of children with ASD were significantly increased, and serum 5-HT levels were decreased. Moreover, statistically significant changes were observed in mRNA expression levels of RAR α, RAR γ and TpH 1 after VAS compared to baseline. This study suggested that VA supplementation may improve symptoms and reduce 5-HT levels in children with ASD, indicating that VA supplementation is a reasonable therapy at least for a subset of children with autism.
"Children with autism were requested to complete an interview with a developmental pediatrician and submit to a baseline blood collection. Then a single vitamin A supplementation (VAS) at a dose of 200,000 IU (WHO, 2011) was performed in the thirty-three ASD patients. All evaluations and blood collection were conducted again 6 months after VAS, based on the principle that a single, large dose of vitamin A is well absorbed and stored in the liver, and then mobilized, as needed, over an extended period of time."
The WHO document they are referring to is this one:
Guideline: Vitamin A Supplementation in Infants and Children 6–59 Months of Age - NCBI Bookshelf
Very interesting. I feel as though Vitamin A might be a wee bit misunderstood. It is generally the feeling that vitamin A deficiency is not an issue in Western countries. @Travis made that point in another thread recently. Maybe full on deficiencies are rare, but that doesn't mean it's not possible that peoples health is suffering to some degree by sub-optimal levels of this vitamin. It also doesn't mean that we wouldn't benefit from more. Women are told not to supplement with vitamin A during pregnancy. There is a great fear of it causing birth defects. When I looked into the history of this fear and the teratogenic effects of vitamin A, the evidence seemed weak in my opinion. From what I remember it was based of a New England epidemiological study and did not differentiate between synthetic form of the vitamin and other forms. Perhaps the rise in autism is in part due to this fear of vitamin A during pregnancy that has taken over? I'm not saying it is or isn't, just throwing the question out there.
There are other nutrients that we benefit from that would be very difficult to actually become deficient in. Glycine is a non-essential amino acid and clearly people would benefit from getting more of this in their diet. Another one is niacin, which the body can make, yet seems to be beneficial if supplemented. I am under the impression we can make taurine as well, yet there seems to be benefit from supplementing that (I don't know much about taurine). I think my point is an obvious one.