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Trending Topic - Do New Parents or Parents-to-be Need to be Concerned with Dietary Arsenic Exposure?
Folate During Pregnancy and Autism - A Recent Study
The authors of an exploratory study, observed a strong relationship between pregnant women’s very high plasma levels of folic acid (>59 nmol/L) and vitamin B12 (>600 pmol/L) and the occurrence of autism in their child (HR: 17.59; P value: <0.001). They also observed that taking prenatal vitamin supplements was associated with a lower risk of autism (HR 0.33 to 0.67 - statistically significant for 3-5 times per week consistent with other frequencies but no dose response relationship noted). They concluded that their findings, "warrant additional investigation and highlight the need to identify optimum prenatal folate and vitamin B12 levels that maximize health benefits, at the same time minimize the risk of excess and its associated adverse consequences such as Autism Spectrum Disorder (ASD).”
This work is observational, so it only notes associations, and these associations do not make sense. Due to its observational design this study did not show any cause and effect relationships. Prenatal vitamin supplements contain more folic acid than can be consumed by eating food, so how did these women with the high levels obtain these high levels when folic acid supplementation was associated with protection from autism in their child? It is possible these high levels are a marker of something going on metabolically. The study results do not suggest that the routine supplementation of folic acid to prevent neural tube defects increases the risk of developing autism rather than a nutrition effect.
There are three main areas of concern:
- It is irresponsible to promote a press release prior to following the standard process of scientific discovery which is a peer review of the study by other researchers.
- It is not clear if autism was actually diagnosed in the children or if they were labeled autistic because of parent report since the abstract states that there was a very high rate of autism in the children (7.7%). This high rate raises questions about the accuracy of this study.
- News articles such as CTV News, Excess Folic Acid During Pregnancy Linked to Autism in Children: Study lead to public concern, with many unsure what to do.
More quality research is needed before any claims or change in practice can be recommended. For more information, see an assessment by The Independent in the U.K., Scientists Urge Caution Over 'Alarmist' Claim of Link Between Pregnancy Folate and Autism.