prenatal folate vs folic acid according to research

Ahh prenatal vitamins.  How does one choose?  Many docs don’t give a specific recommendation, and every brand has something “groundbreaking” to offer.  So how does a woman choose?  Many ask which prenatal vitamin is my fave, and I hate to give the generic answer of “it depends on the situation”.  


Regardless of the situation, there are some things that are pretty consistent when it comes to prenatal vitamins.  One is that I look for methylated folate instead of the synthetic folic acid. Some labels will read 5-MTHF or something like that. 


We all know the importance of this vitamin (B9 is another way to refer to it!) and it’s role in baby’s neural tube development.  Of course, it plays many other roles in the body as well.


5-MTHF stands for 5-5-methyltetrahydrofolatehas important advantages over synthetic folic acid – it is well absorbed even when gastrointestinal pH is altered, and its bioavailability (rate of absorption) is not affected by metabolic defects like MTHFR reductase polymorphism (that approx. 60% of people may have). Using 5-MTHF instead of folic acid reduces the potential for masking symptoms of vitamin B12 deficiency and reduces interactions with certain drugs. Use of 5-MTHF also prevents the potential negative effects of unconverted folic acid in the peripheral circulation.


Folic acid is man-made and needs to be broken down (metabolized) in order to be used properly by the body. Un-metabolized folic acid can accumulate in the body and over time can lead to some health consequences in the long-run (some studies suggest certain cancers!  Yikes!). One study that I have come across suggests that high levels of folic acid is related to cognitive decline in older persons too.


One other concern I have is that prenatal folic acid supplementation may be linked to allergy risk in kiddos later in life.  One study highlighted a positive association of folic acid supplementation in late pregnancy and asthma risk. In other words, high levels of FOLIC ACID later in pregnancy was related to higher risk of kids developing asthma as they got older.  The authors point out that risk was not associated with FOLATE intake.  


Another study related allergy risk and folic acid intake was presented at the American Academy of Allergy Asthma and Immunology joint congress in 2018 suggesting that folic acid exposure in utero is related to food allergy development in kids.  In the study, scientists found that higher levels of unmetabolized folic acid measured at birth was associated with the development of food allergy.


The studies focusing on folic acid and allergy risk are VERY limited, and I do NOT want to come across as a fear-monger.  Normally I do not base recommendations off of two studies.  But with this allergy data compounded with so many other reasons why folate is shown to be preferred over folate, I feel like it is worth the extra cost to forego the folic acid in prenatal supplements.


PS- If a woman is undergoing IVF, I like to recommend that they take over 800 mcg of folate in their prenatal vitamin. This is based off of a recent study suggesting a relationship between supplementation of certain micronutrients and higher chance of IVF success.  One of these micronutrients is folic acid (folate), and taking in at least 833 mcg appears to offer some benefit.  This is only based off of one study, but it is the only study I have come across that has given specific recommendations on folate supplementation amounts for IVF patients.  You work with what you got, right? 

Folic acid is one deal-breaker when it comes to selecting prenatal vitamins in my book.  Want to dig deeper into what I look for with specific recs for TTC and pregnancy? Click here to check it all out!