Prenatal vitamins – including vitamin D – reduced autism by 40% – May 2011

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Prenatal Vitamins, One-carbon Metabolism Gene Variants, and Risk for Autism.

Epidemiology. 2011 May 23.

BACKGROUND:
Causes of autism are unknown. Associations with maternal nutritional factors and their interactions with gene variants have not been reported.
METHODS:
Northern California families were enrolled from 2003 to 2009 in the CHARGE (CHildhood Autism Risks from Genetics and Environment) population-based case-control study. Children aged 24-60 months were evaluated and confirmed to have autism (n = 288), autism spectrum disorder (n = 141), or typical development (n = 278) at the University of California-Davis Medical Investigation of Neurodevelopmental Disorders Institute using standardized clinical assessments. We calculated adjusted odds ratios (ORs) for associations between autism and retrospectively collected data on maternal vitamin intake before and during pregnancy. We explored interaction effects with functional genetic variants involved in one-carbon metabolism (MTHFR, COMT, MTRR, BHMT, FOLR2, CBS, and TCN2) as carried by the mother or child.

RESULTS:
Mothers of children with autism were less likely than those of typically developing children to report having taken prenatal vitamins during the 3 months before pregnancy or the first month of pregnancy (OR = 0.62 [95% confidence interval = 0.42-0.93]).
Significant interaction effects were observed for maternal MTHFR 677 TT, CBS rs234715 GT + TT, and child COMT 472 AA genotypes, with greater risk for autism when mothers did not report taking prenatal vitamins periconceptionally (4.5 [1.4-14.6]; 2.6 [1.2-5.4]; and 7.2 [2.3-22.4], respectively). Greater risk was also observed for children whose mothers had other one-carbon metabolism pathway gene variants and reported no prenatal vitamin intake.

CONCLUSIONS:
Periconceptional use of prenatal vitamins may reduce the risk of having children with autism, especially for genetically susceptible mothers and children.
Replication and mechanistic investigations are warranted.

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Study was cited 405 times as of June 2025

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See also VitaminDWiki

• Overview - Autism and vitamin D
• Most Autism Risk factors are associated with low vitamin D - March 2014
• Autistics have half of the response to Vitamin D – RCT Oct 2018
• Autism decreased in 8 out of 10 children supplemented with vitamin D – April 2015
• Autism rate cut in half when multivitamins (including vitamin D) used during pregnancy – Oct 2017
• Vaccines increase the risk of autism (25 studies) - Feb 2025
• Autism and ADHD type disorders were 14X more likely in survey of extreme preterm vaccinated infants - April 2017
• Autism is strongly associated with 31 gut microbiota (bacteria, archaea, fungi, and viruses) – July 2024
• Autism risk is reduced by Vitamin D – early pregnancy or chlldhood – Umbrella review – July 2024

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