Lead exposure during pregnancy can harm a child’s developing brain, increasing the risk of autism-related behaviors. Some evidence suggests that folate, a B vitamin, might help protect against lead’s neurotoxic effects. A recent study found that higher folate levels during pregnancy may help reduce the risk of autism-like behaviors in children exposed to lead before birth.

Researchers analyzed data from a large mother-infant cohort study that tracked participants from pregnancy through early childhood. They measured blood lead levels and plasma folate concentrations during the women’s first and third trimesters. They assessed the children for autism-related behaviors when they were three to four years old. They also examined whether folic acid supplementation and MTHFR, a maternal genetic variant influencing folate metabolism, affected these associations.

They found that third-trimester blood lead levels were associated with more autism-like behaviors in children whose mothers had low third-trimester folate levels. They did not observe this association among mothers with higher folate levels. Additionally, folic acid supplementation appeared to reduce the harmful effects of lead exposure. The MTHFR genetic variant influenced the findings, but the effects were not statistically significant.

These findings suggest adequate folate levels during pregnancy may help protect against the neurodevelopmental harm linked to prenatal lead exposure.

Folate is the natural form of vitamin B9 found in foods, while folic acid is the synthetic form used in supplements and fortified foods. Folic acid has higher bioavailability, meaning the body more readily absorbs it than naturally occurring folate. Learn more about folate in this clip featuring Dr. Bruce Ames.