Autism is characterized by communication deficits, impairments in social interaction, intellectual disability, and repetitive behaviors.
The study, conducted by researchers at UC Davis MIND institute and published in the American Journal of Clinical Nutrition, adds to the researchers' earlier work, which found women were less likely to have a child with autism if they consumed prenatal vitamins around the time of conception.
In this study, the team set out to determine if the protective effect in those supplements was folic acid. According to the findings, women who are trying to conceive a child or those who have already conceived should consider taking folic acid supplements.
The researchers discovered that women were less likely to have a child with autism if they consumed the recommended amount of folic acid during the first month of pregnancy, specifically, when the mother and/or her child had a specific genetic variant (MTHFR 677 C>T). This variant is associated with less efficient folate metabolism.
Lead study author Rebecca J. Schmidt, assistant professor of public health sciences in the UC Davis School of Medicine and a research with the UC Davis MIND institute, explained:
"This research is congruent with the findings of earlier studies that suggest that improved neurodevelopmental outcomes are associated with folic acid intake in early pregnancy. It further supports recommendations that women with any chance of becoming pregnant should consider consuming folic acid at levels of 600 micrograms or greater per day."
Irva Hertz-Picciotto, chief of the division of environmental and occupational health in the Department of Public Health Sciences and MIND Institute researcher said:
"What's reassuring here is knowing that, by taking specific action in terms of their intake of folic acid from food or supplements, women can reduce the risk of autism spectrum disorder in their future children."
According to the researchers, folic acid helps protect against problems with embryonic brain development by facilitating DNA methylation reactions that can change the way the genetic code is read. They state that adequate intake of methyl donors, such as folic acid, could be especially important during the time a women conceives.
The team examined data on 835 Northern California women who had children aged 2 to 5 years old with autism, developmental delay or typical development. All the mothers took part in the Childhood Autism Risk from Genetics and the Environment (CHARGE) study between 2003 and 2009.
The investigators evaluated the average amount of folic acid each woman consumed daily and the frequency of consumption. They gathered information from study participants 3 months before they became pregnant, and then again when they were pregnant.
They found that mothers of children with autism reported less folic acid intake during their first month of pregnancy than mothers of typically developing children, who reported more likely to meet intake recommendations.
Lower folic acid intake found among many pregnancies that resulted in offspring with developmental delayFurthermore, study participants were less likely to have a child with autism if the amount of folic acid they consumed increased. During the three months before pregnancy, mothers of children with developmental delay tended to have lower estimated folic acid intake.
In many countries today, including the USA, several grain products are fortified with folic acid
According to the researchers, at least 69% of mothers of typically developing children met the recommended daily guidelines for folic acid, with an average of 779 micrograms per day. 54% of mothers of children with autism met the daily guidelines, with an average of 655+ micrograms per day.
Earlier studies have shown that consuming supplemental folic acid before and during early pregnancy can prevent up to 70% of neural tube defects, or improper formation of the embryonic brain and spinal cord, as well as securing improvements in other social, attention and behavioral outcomes in the developing child.. These effects were stronger when the mother and/or child carried the MTHFR 677 C>T gene variant.