Concerns About Folate Causing Autism Are Premature

Yesterday’s press release was potentially dangerous.

Mary Altaffer / AP

Yesterday morning, the Johns Hopkins University department of Media and Public Relations released information that, as intended, created news.

The written press release was titled “Too Much Folate in Pregnant Women Increases Risk for Autism, Study Suggests.”

The subsequent headlines were similar: “Autism Linked to Overdose of Folate and Vitamin B12 During Pregnancy” (The Telegraph), “Study: Too Much Folate, B12 In Pregnant Women Can Multiply Autism Risk By 17.6” (CBS), “A Study Asks: Too Much Folic Acid a Cause of Autism?” (Fox News). I could go on.

In most of the world, taking supplemental folate (sometimes referred to as folic acid) is recommended to everyone who’s pregnant or thinks they might possibly become pregnant. Yesterday’s headlines imply that millions of conscientious, well-meaning people could be putting their children at risk of autism spectrum disorder (ASD).

So it’s important to note that this does not appear to be the case.

Taking supplemental folate during pregnancy is still firmly, clearly recommended. Yesterday’s study, actually, confirms that. Of the 1,391 people in the preliminary findings released today, those that took prenatal vitamins were only less likely to have a child who would later be diagnosed with ASD. This is a finding that is supported by some previous research. (Other previous studies showed no relationship.)

But the headlines are also somewhat accurate. This highlights a distinction that is extremely important for the future of this research. For decades, we’ve known that folate plays a critical role in formation of the spine of a fetus. When a pregnant person doesn’t take in enough folate, the fetus has a much greater risk of being born with a splayed vertebral column (spina bifida), or a similar abnormality on the spectrum neural tube defects.

These debilitating spinal birth defects became more common (as did other symptoms of folate deficiency), as our diets came to consist of ever more processed foods. While folate is abundant in fruits and vegetables, highly processed foods tend to be stripped of nutrients and so must be “fortified” with synthetic versions of the nutrients. Some countries, including the U.S., passed laws requiring that folate be added to processed foods.

To be doubly safe–females of childbearing age have long been advised to take supplemental folate. (“Prenatal multivitamins” are loaded with folate.)

The effort was extremely effective. Rates of neural tube defects plummeted.

But they didn’t go to zero, and that’s because a lot of people still don’t get enough folate around the time that they conceive, and in the early stages of pregnancy.

So the message from today’s news is potentially dangerous, if it detracts from that momentum.

What is unique today is the finding that blood tests done around the time of birth found that about 10 percent of mothers had excessively high levels of folate and/or vitamin B12 in their blood. Those people had an increased risk of having a child who would later be diagnosed with ASD.

I spoke with one of the researchers, Dani Fallin, who is chair of the department of mental health at Johns Hopkins. She specified that the team did not have access to data that could correlate the use of supplements with the high levels of folate or B12 in people’s blood. “We would want to understand why these women have such high levels of folate in their blood,” she explained, “whether it's about fortification of foods, supplementation, genes and enzymes involved in metabolism, or a combination of those things.”

If anything, these findings would suggest that one day it might be worthwhile to consider screening pregnant women with blood tests to look for toxic levels of folate or B12. Fallin put the findings cautiously, succinctly: “We see this as evidence that there is a subset of people for whom excessively high levels of folate (in their blood) might be at risk for autism (in their children).”

At this point, though, the evidence is extremely premature. The findings have not been peer-reviewed or published in a journal; the press release referred only to a brief scientific abstract that is being presented at a conference this week.

It remains to be seen if the findings hold up to the scrutiny of peer review and, so, warrant publication in a medical journal. Even if they do, after that, the correlation would need to be seen again, and again, in multiple studies, before it could reliably be said to exist. Then, if it does exist, the challenge would be to attempt to figure out what drives those elevated levels in a person’s blood.

Which is to say, we are so far from saying that consuming excessive folate causes autism. But we can clearly say, as we have for years, that maternal deficiencies in folate cause neural tube defects—thousands every year—and these are readily prevented by consuming enough folate.

None of this leaves the average person in a place other than they were before yesterday. Anyone who’s eating folate pills or multivitamins by the handful should stop doing that, but I would’ve told them the same thing last week. There’s never been reason to assume that it was prudent to consume enormous amounts of folate or any other substance.

Fallin told me she’s done a lot of interviews in the last couple days, and that she’s “slightly nervous” that her findings will be misconstrued. “There's this danger that the message would be that folate supplementation is bad. And that's not at all what we saw.”

This is the danger that made me feel like I needed to write about the study. It could have been avoided if Hopkins didn’t issue a press release, essentially asking media outlets to take this information—from an unpublished abstract—to lay audiences.

I asked their director of public relations Stephanie Desmond what their rationale was. As part of a longer email reply, she noted that publicizing abstracts is a common practice, and that “because the science presented at this meeting may have public health implications if confirmed in additional studies, we felt that we should keep the public informed about these scientific developments as they emerge.”

The press release, Fallin corroborated, came about because the International Meeting for Autism Research is happening this week. “The organizers of the meeting select presentations that they think are newsworthy to create a press presentation,” she noted. “The organization that runs the meeting wants to make sure that ASD research and findings are communicated to the public.”

And, these findings will go to peer review?

“We intend to submit literally this week,” she said.

I understand that if people have new information that, they believe, indicates an immediate threat to fellow humans—that there is lead in drinking water, say, or that a subway tunnel is structurally unsound—the instinct to get that information to the public right away is appropriate. They could wait a few months to quadruple-check the findings with an international consortium of experts, but that also might not be prudent.

In this case, though, the information is not actionable for the everyday consumer of health news. The correlation is potentially important, rather, for researchers hoping to understand the mechanisms behind ASD at a cellular level over the long term. Folate and B12 are involved in multiple pathways, including one-carbon transfer, which is critical to turning cells on and off at the right time during development. It is logical that if the lack of dietary compounds like these can be so damaging to fetal development, then excesses could also be damaging. As Fallin put it, “You can imagine that abnormalities in that system can have effects at both ends of extreme levels.”

As for transparency, this and all data should be available to the public as often and openly as possible. But there is rarely cause for a press release about a single study; especially one not yet published. This is no exception.