Among the countless nutrition controversies in the Google-sphere, it's indisputable that folate is one of the most essential nutrients during pregnancy. Folate deficiency increases the risk of having a baby with a neural tube defect by 50%-70%.* It’s a big deal. And it means you need to plan ahead — prevention of these birth defects requires getting enough folate in the months prior to pregnancy.
Despite the broad acceptance of folate as an important nutrient for a healthy pregnancy, the controversy arises around which molecular form is best to include in prenatal multivitamins. It’s a public health tug of war between the less costly, well-studied, synthetic folic acid compared to the more bioavailable and naturally occurring methylfolate.*
In this post, you’ll find the need-to-know details to make an informed decision about what’s best for you. To summarize what we'll dive into below:
- Yes, you do need to take a prenatal multivitamin that contains some form of folate, ideally starting three months or more before getting pregnant, according to Mayo Clinic.
- We recommend the biologically active form, methylfolate, over folic acid because it’s more absorbable (and poses fewer health risks) for more people.*
First, a quick overview of the different types of folate
Folate, also known as vitamin B-9, is the umbrella term for all forms of the nutrient:
- Folic acid is the synthetic form (aka human-made) of folate, commonly found in processed foods, prenatal vitamins, and other dietary supplements. Aside from the fortification of foods with folic acid (which was done to prevent neural tube defects), you won't find it in plants or vegetables.
- Methylfolate (aka L-methylfolate, 5-MTHF, 5-methyltetrahydrofolate) is the biologically active, natural form found in foods like leafy greens, whole grains, beans, eggs, and more. "Biologically active" means it can be readily used by the body. (By contrast, when you eat foods fortified with folic acid, your body needs to convert that folic acid into 5-methyltetrahydrofolate before it can be utilized.)
(It's important to note here that any form of supplementation is technically synthetic, but your body doesn't know the difference.)
Why is folate such a big deal?
Folate is needed for the synthesis of DNA and RNA, which in turn enables cell regeneration in your body and cell division for fetal development. As you can imagine, if folate is in short supply and cells cannot divide and proliferate as they should, issues can arise. The most widely known consequences include babies born with spina bifida (when the spine and spinal cord don't form properly) and other neural tube defects (NTDs): issues with fetal spine, spinal cord, or brain development (which happens in early pregnancy, during the first trimester).
The bright side of this folate story is that NTD birth defects are largely preventable. Multiple randomized control trials (the gold standard for medical research) have demonstrated the efficacy of folic acid supplementation for preventing NTDs.* In response, in 1998, the Food and Drug Administration (FDA) mandated that all flour products — breads, breakfast cereals, pastas, etc. — be enriched with folic acid.
(Note that gluten-free products are not included in this mandate and are typically not enriched. If you eat a largely gluten-free or whole foods-based diet, you may not be getting enough folic acid intake from your food.)
Does folic acid fortification save the day? Not exactly
This mandatory folic acid enrichment of grains decreased the prevalence of infants born with NTDs by 36%. But while the mandate for fortified foods with folic acid was initially viewed as a huge public health victory, unfortunately, it hasn’t proven to be the panacea many had anticipated. National data in the US estimates that decades later, nearly 20% of people with ovaries in their reproductive years are still not getting enough folate — and around 3,000 births are affected by NTDs every year in the US.
Another potential issue with folic acid supplementation or food fortification is that it might not be the most effective form of folate intake for all people — depending on the individual's health and genetics.
Why choose methylfolate over folic acid supplements?
Methylfolate is an easier-to-absorb folate option. Your body needs to break folic acid down into 5-MTHF before it's usable. Each individual’s ability to make this conversion to the bioavailable 5-MTHF varies based on liver function, genetics, alcohol consumption, and gut health (those with impaired absorption due to conditions like celiac disease or irritable bowel disease are at greater risk of folate deficiency), among other factors.
Genetic variants in the MTHFR gene can reduce your body’s natural ability to process folate. These variants may limit the absorption and utilization of folic acid — leading to an increased risk of having an infant with a NTD. Just to be clear: There’s no evidence that people with these genetic variants should avoid folate and folic acid, and ASRM and ACOG still recommend folic acid for everyone. If you want to dive really deep into this topic, check out “MTHFR: Addressing genetic counseling dilemmas using evidence‐based literature.”
Since folic acid supplements or fortification may not meet the nutritional needs of all people (and since proactive genetic testing for variants in genes like MTHFR isn't recommended), a cautious approach is to opt for methylfolate — the biologically active form of folate that's easier to absorb for more people.*
Like so many health issues, ultimately, you should make an informed decision about what’s best for you with the advice of a healthcare provider who knows your personal medical history.
When should you begin taking a prenatal with folate?
The neural tube forms in the first four weeks after conception (before many people even realize they’re pregnant!). If you can plan ahead, it’s ideal to take a prenatal supplement with folate (methylfolate is our preference) for at least three months before trying to conceive so you can build up the levels of the nutrient in your body before pregnancy. If you can take one up to a year before conception, all the better (one study found that reduced the risk of preterm delivery for the pregnant women who participated).*
How much folate do you need?
The American College of Obstetricians and Gynecologists (ACOG) recommends at least 400 micrograms (mcg) DFE (dietary folate equivalent) per day of supplemental folate, from preconception through at least the first 12 weeks of pregnancy. Many providers (including myself, a nutritionist) also recommend continuing to supplement your folate levels through the rest of pregnancy and postpartum to meet the continued increase of nutritional needs.
What about food-based folate?
As an advocate for a food-first approach, I can’t overlook the importance of eating food rich in folate, like green leafy vegetables (particularly spinach), brussels sprouts, asparagus, oranges, avocado, milk, yogurt, nuts, and beans.
But can you have too much folate in your system if you’re getting it from food sources as well as a supplement? There currently aren’t any guidelines that vary recommended amounts of folate supplementation based on food intake. But since folate is water-soluble, any excess nutrients will leave your body naturally. That said, in terms of the upper limit of folate supplementation, the National Institutes of Health (NIH) recommends no more than 1,000 mcg of folic acid per day. As for the amount you’re getting from what you eat? Overdosing on high levels of a food-based form of a nutrient isn’t a thing.
*This statement has not been evaluated by the FDA.