Should Women of Childbearing Age Stop Taking Folic Acid Supplements? Recent Media Would Suggest They Should. Research Suggests Otherwise

pregnant-with-healthy-foodRecent media reports of unpublished research suggest women who consume too much folic acid (the synthetic form of folate) during pregnancy could double her child’s risk for autism spectrum disorders. However, let’s look at what we know so far about this study from the Johns Hopkins Bloomberg School of Public Health.

  • Data are based on 1,391 mother-child pairs in the Boston Birth Cohort, a mostly low-income minority population.

  • While participating mothers were followed for several years after delivery, blood folate levels were only checked once within the first one to three days after delivery.

  • Findings indicate that, while one in 10 of the women had what is considered to be an excess amount of blood folate, six percent had an excess amount of vitamin B12 in their blood.

  • Most of the mothers in the study reported taking multivitamins during their pregnancies – which would include folic acid and vitamin B12.

  • The researchers found a correlation between mothers with a very high level of blood folate right after childbirth and children whose risk for autism spectrum disorder was doubled.

Now, let’s put these findings into context.

  • Taking a snapshot at one point in time, in this case measuring blood folate levels once and then making a correlation about something years down the road, doesn’t always paint an accurate picture or convey accurate assumptions. For example, if someone took a picture of you one time while you were crying, and then ran into you several years later, would it be safe for them to assume that you’d been sad the entire time? Probably not. Further, measurement of blood folate is more a marker of recent dietary intake and may not reflect long-term folate status. A better indicator of long-term folate intake is erythrocyte folate concentration, just as Hemoglobin A1c is a better indicator of long term blood glucose control than a fasting blood glucose test would be.

  • Even the researchers stated they don’t know why some of the women had excess levels of folate in their blood. They speculate it could be that the women consumed too many folic acid-fortified foods (which is unlikely), took too many supplements, or that some women had a genetic predisposition to absorbing more folate and/or metabolizing it at a slower rate, contributing to excess amounts in the blood.

  • Lastly, let’s not forget that many children between the ages of one to 13 exceed folic acid intake recommendations. Research indicates that, when considering folic acid from both food and supplements, 30 – 66% of children between the ages of one to 13 exceed the Upper Limit intake recommendation for Dietary Folate Equivalents (300 – 600 mcg per day depending on age). It begs the question, is the increased risk alleged in this one unpublished study due to high folic acid intake by the mothers, or by the children?

Women planning to become pregnant, and who are pregnant, are told they need enough folate/folic acid to prevent spina bifida and anencephaly. Folic acid supplements typically contain 400 mcg per dose. Women of childbearing age are recommended to consume 400 mcg, pregnant women are recommended to consume 600 mcg, and lactating women 500 mcg. Due to the increased folate needs during pregnancy, the American College of Obstetricians and Gynecologists recommends pregnant women take a prenatal vitamin to ensure adequate folate intake.
Folate is a B vitamin also found naturally occurring in many foods such as spinach, Brussels sprouts, and asparagus. Because cereals and grains are so popular in the American diet, since January 1998 the U.S. Food and Drug Administration (FDA) has required food manufacturers to add folic acid to enriched breads, cereals, flours, cornmeals, pastas, rice, and other grains. In April 2016 the FDA also stated that manufactures could voluntarily add folic acid to corn masa flour.
The bottom line: There is a reason why public health recommendations have long called for adequate folate intakes for women of childbearing age and those who are already pregnant or lactating. Unfortunately, many women in the U.S. are consuming folate at sub-optimal levels, increasing their risk of having children with preventable neural tube defects. As a health professional I find it vehemently frustrating to listen to news stories about unpublished research alleging that such an important public health priority be taken with a grain of salt. Reporting in ways such as this is only doing women of childbearing age, and their potential children, a drastic disservice. What we should instead be doing is analyzing the findings when they are published and considering them in the context of the vast body of existing research on folic acid intake. Most importantly, let’s not let the allegations of one unpublished study change the way we look at prevention. Women of childbearing age and those who are pregnant or lactating should continue to follow the advice from their medical providers about folic acid intake. Your baby will thank you.