Updated August 2018
Is there a link between vitamin D deficiency in expectant moms and Autism? We investigated…
Recent research suggests there may be a correlation between severe prenatal maternal vitamin D deficiencies (as defined as less than 10ng/mL) and Autism Spectrum Disorder (ASD)-related behaviors or diagnoses.
The findings are associative, meaning they don’t necessarily indicate that a deficiency in vitamin D causes ASD. So until we have evidence from randomized-control studies, or even just studies that administer vitamin D supplements during pregnancy, we can’t confirm that a prenatal deficiency in vitamin D actually leads to ASD.
That said, treating severe vitamin D deficiency during pregnancy (and perhaps early childhood) could potentially minimize one of multiple interacting risk factors for ASD.
The first studies addressing the relationship between prenatal vitamin D deficiency and ASD were based on reports out of Sweden in 2009. There, researchers found that among recent Somali immigrants (to Sweden, which is located at a very high latitude), the rate of ASD was 3-4 times higher than among the general population. They speculated that a rapid loss of access to vitamin D (due to their move from their previous equatorial climate) might be to blame; when our skin is exposed to sunlight (specifically the UVB rays from sun that is high in the sky), our bodies produce more vitamin D.
Scientists uncovered a similar phenomenon in Minnesota, where Somali refugees also had higher-than-expected rates of ASD. “What seemed to link the two regions was the fact that Somalis were getting less sun than in their native country—and therefore less vitamin D,” Gabrielle Glaser reported.
Maternal Vitamin D
More recently, other types of studies also suggest a link between very low vitamin D levels during pregnancy and neurological disorders, including ASD.
In a study of 4,000 babies and mothers in the Netherlands, researchers measured maternal vitamin D levels at 20 weeks gestation, and also measured cord blood vitamin D levels in newborns.
Their findings “suggest that infants exposed to persistent low vitamin D from mid-gestation until birth may be at risk for autism-related traits [not formal ASD diagnoses], whereas this was not identified in those with deficiency at only one time point.”
Another study (involving the same babies and mothers), reported that children born to women in the vitamin-D-deficient group at 20 weeks gestation had a more than twofold higher risk of an ASD.
Though research is still preliminary, it’s definitely is something to think about. For more on the importance of prenatal vitamin D and vitamin D supplements, click here.