Children whose mothers took multivitamins during pregnancy are about 30 percent less likely to develop autism with an intellectual disability, according to a new study.

When researchers from Drexel University studied data collected over more than a decade in Stockholm, Sweden, they found that the decline in risk linked to multivitamin use only seemed to be tied to autism with intellectual disabilities attached. The odds of developing autism without an intellectual disability did not seem to be affected, researchers reported.

“A potential link between supplement use during pregnancy and autism is intriguing because it suggests a possible avenue for risk reduction,” said Brian Lee, Ph.D., an associate professor and senior author of the study, which was published in BMJ (formerly The British Medical Journal).

Data for the study was drawn from children living in Stockholm County, Sweden, for at least four years between 2001 and 2011. Only children ranging in age from four to 15 at the end of 2011 were included.

To make results more robust, data from siblings was also taken into account to help offset some of the unseen factors in autism development, like heritability or otherwise healthy behaviors, researchers explained.

Little is known about how diet during pregnancy might affect the risk of a child developing autism, according to the study’s lead author, Elizabeth DeVilbiss, Ph.D., a recent graduate of the Dornsife School of Public Health at the university.

“There have been more studies in recent years about varied aspects of diet during pregnancy and autism risk involving multivitamins, iron, folic acid, vitamin D, and more, but the evidence is still inconclusive,” said DeVilbiss, now a postdoctoral fellow at the Eunice Kennedy Shriver National Institute of Child Health & Human Development. “More work needs to be done in this area to clarify these potential relationships.”

Hoping to clarify autism risk linked to diet during pregnancy, DeVilbiss, Lee and their team, which also included researchers from the University of Bristol and the Karolinska Institute in Sweden, also looked for potential changes in autism risk related to taking supplemental folic acid and iron. Both are supplements that have commonly been recommended for pregnant women.

Neither appeared to have a significant effect on a child’s autism development, researchers discovered.

However, there is room for other factors to have influenced those results.

“We cannot rule out potential contributions by iron and folic acid,” DeVilbiss said. “Diet during pregnancy is complicated, and there are important factors we can’t assess with our data, such as dietary intake, dose, and timing. This is clearly an area for future work.”

In that future work, the hope is that more specifics can be nailed down, the researchers said.

While the new study found links between multivitamin use and potential protection against autism with intellectual disabilities, a “link” isn’t the same as a “cause” in research, the researchers said, noting it comes down to other factors and variables.

“If there is a causal relationship, we also need to understand whether there is a critical window for exposure, and what specific nutrients and amounts may be required for protection,” DeVilbiss said.

Source: Drexel University

Vitamins During Pregnancy Tied to Less Risk of Autism With Intellectual Disability