Folic acid may mitigate link between lead exposure during pregnancy and autistic behaviours in children

A new study by Simon Fraser University researchers has found that folate may weaken the link between blood-lead levels in pregnant women and autistic-like behaviours in their children.

Researchers from SFU's Faculty of Health Sciences, led by PhD candidate Joshua Alampi, published the study in the journal Environmental Health Perspectives.

"Folic acid supplementation during pregnancy has numerous benefits to child health, especially brain development," says Alampi. "Our study suggests that adequate folic acid supplementation mitigates the neurotoxic effects of lead."

The SFU-led study is the first to observe that adequate folic acid supplementation may reduce the risk between gestational lead exposure and autism. It found that associations between blood lead levels and autistic-like behaviours in toddlers were stronger among pregnant women with less than 0.4 milligrams per day of folic acid supplementation.

Folate and folic acid, a synthetic version of folate found in fortified food, have long been established as a beneficial nutrient during pregnancy. Folate consumption plays a key role in brain development and prevents neural tube defects. Previous studies have found that the associations between autism and exposure to pesticides, air pollutants and phthalates (chemicals commonly found in soft plastics) during pregnancy tend to be stronger when folic acid supplementation is low.

The team used data collected during 2008-2011 from 2,000 Canadian women enrolled in the MIREC study (Mother-Infant Research on Environmental Chemicals). The MIREC team measured blood-lead levels collected during first and third trimesters and surveyed participants to quantify their folic acid supplementation. Children born in this cohort study were assessed at ages three or four using the Social Responsiveness Scale (SRS), a common caregiver-reported tool that documents autistic-like behaviours in toddlers.

However, researchers also found that high folic acid supplementation (> 1.0 milligram per day) did not appear to have any extra benefit for mitigating the neurotoxic effects of lead exposure.

"The study's finding aligns with Health Canada's recommendation that all people who are pregnant, lactating, or could become pregnant, should take a daily multivitamin containing 0.4 milligrams of folic acid."