Women who take multivitamin supplements during pregnancy may reduce their child’s risk of autism spectrum disorder according to new research. Though the study in question, published in the British Medical Journal, applied three separate analytical methods to data on nearly 300,000 mother-child pairs in Sweden, it by no means suggests supplements eliminate any chance of autism. Instead, the data underscore the importance of prenatal nutrition and raises important questions for future preventative research.
“A single observational study cannot establish cause and effect,” study coauthor Elizabeth DeVilbiss of Drexel University told Fatherly. “However, a potential link between supplement use during pregnancy and autism with intellectual disability is intriguing because it suggests a possible route for risk reduction.”
While the cause of autism is unknown, there’s a growing body of research that suggests that it develops in the womb. Likewise, there’s plenty of evidence illustrating how maternal nutrition affects neural development, which could influence how autism develops, studies say. Research has previously explored the link between autism risk and supplements such as folic acid and other multivitamins, but results have been inconsistent and many of these studies do not distinguish between autism with and without the presence of an intellectual disability.
For the current study DeVilbiss and her team looked at data on 273,107 mother-child pairs obtained from the Stockholm youth cohort, a population register in Sweden, where cases of childhood autism were identified as well. Mothers self-reported their use of folic acid, iron, and multivitamin supplement use at their first antenatal as well. “We observed associations between multivitamins and ASD with, but not without a co-occurring intellectual disability,” says.
Conversely, analysis showed that folic acid and iron didn’t seem to make much of a difference.
It’s important to note that the study comes with a number of caveats. First, the data could not determine a critical window for exposure, what specific nutrients or combinations of nutrients caused this, or what dose is required. The findings are difficult to translate to the U.S. because the research took place in a country where prenatal supplements are subsidized. Supplements are also very much a growth industry and part of a global market projected to be worth $278.02 billion by 2024, and in the U.S. they’re largely unregulated. The FDA is technically in charge, but does no quality control. So there’s reason to believe that many multivitamins don’t do a damn thing.
DeVilbiss could not confirm if it was more effective for women to consume important nutrients through foods rather than supplements, as this was not compared in the current study. Still, whole foods a generally higher in nutrients and absorbed faster by the body and this is probably a best practice throughout life, including during pregnancy — along with prenatal vitamins as directed by a doctor.
The findings do not call for any specific changes in supplement guideline for pregnant women, but they do call for further research to improve this assessment of maternal diet during pregnancy.
“These results on their own should not change current practice,” DeVilbiss acknowledges. “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.” Until they do, the important takeaway is that the nutrients kids are exposed to in the womb matter, likely more than scientists know, so keep eating those vegetables as well.