Autism spectrum disorder (ASD) is now common while it was rare when I was a child. The theory that the increased incidence is simply due to better detection is absurd as it assumes that parents, pediatricians and schoolteachers missed this condition in the 1950s, 60s and 70s, which in many cases, is not a subtle condition. That theory has poor face validity.
Also, socioeconomic status must be controlled for in any prevalence study of ASD. When socioeconomic status is controlled for, African American individuals who belong to a higher socioeconomic status are twice as likely to have a child with ASD, as compared to Whites from the same socioeconomic status.
But I digress. I want to share with you some new research just published out of China that found in a cross sectional and case-control study, that the higher your vitamin D level, the milder your autism.
Chinese researchers have recently replicated a similar Saudi Arabian study. Like the Saudi Arabian study, the Chinese study showed ASD severity is inversely associated with vitamin D blood levels.
The researchers studied 48 children with ASD and compared them to 48 matched controls.
They found mean vitamin D levels were a little lower in the ASD children, 19.9 vs. 22.2 ng/ml (p=.002).
When the researchers looked at blood levels of each specific child with ASD and compared them to autism severity, they found that the scores on the Childhood Autism Rating Scales were inversely associated with 25(OH)D levels (r=.41), the higher the vitamin D blood level, the less severe the autism In their graph, the two children with the mildest ASD had the highest 25(OH)D levels, while the severe ASD children all had 25(OH)D levels below 25 ng/ml.
The authors concluded,
“These results indicate that lower 25(OH) D levels may be independently associated with the severity of ASD among Chinese patients, and lower serum 25(OH) D levels could be considered as an independent risk factor for ASD.”
This study does not prove causation; it could be that children with less severe autism simply go outside and get more sun exposure. We still need lots more research looking at vitamin D and ASD, and more studies like these are sorely needed.
As an aside, I am so convinced vitamin D will help ASD, I am starting a small part-time private practice based on using supplements like vitamin D to help treat ASD. In addition to vitamin D, I believe other supplements will have a treatment effect in ASD, especially those that increase cysteine intake. The presence of cysteine in the intestine is the rate-limiting step for the production of glutathione, the brain’s master antioxidant.
If you are interested, or know someone who might be, please email me at [email protected].