Are you pregnant?
Are you taking a prenatal vitamin every day?
Why in the world would a midwife say that it is good to NOT take a prenatal vitamin every day? Because prenatal vitamins have a LOT of folic acid. And more is not always better.
Folate is a a B vitamin (B9, or pteroyl-L-glutamate) that is used in the body for cell growth and proper DNA function. Having an adequate amount of folate is crucial for the development of the embryo, especially for the proper closure of the neural tube. Folic acid is the synthetic version of folate.
When the embryonic neural tube forms properly, the resulting baby has a intact brain, skull and spine. When something goes awry with the closure of the neural tube, it is referred to as a neural tube defect. Neural tube defects can be minor (such a Spina Bifida Occulta) or devastating (like myelomeningocele or anecephaly) Approximately 0.2% of births are complicated by neural tube defects. That translates to about 3,000 babies every year in the US.
It has been a long standing recommendation that woman capable of getting pregnant consume 400 mcg daily of folic acid to reduce the risk of giving birth to a child with a neural tube defect. This amount of folic acid should be consumed from the month prior to pregnancy until the end of the first trimester. Since at least half of conceptions in the US are not planned, the recommendation is for all women of childbearing age to consume at least 400 mcg daily of folic acid in the form of food and/or supplement. The Center of Disease Control (CDC), first made this recommendation in 1992.
Around the world, the fortification of foods, primarily grain products, with folic acid has been going on for decades. In the US, mandatory fortification of grain products was authorized in 1996 and fully implemented in 1998. Since that time, the incidence of neural tube defects in the US has decreased by approximately 25%.
So why would I, a midwife, someone that loves women and babies, a professional that strives for healthy clients, ever suggest that a prenatal vitamin might NOT be a good idea? Because more is not always better.
The recommendation for 400 mcg of folate (in diet and/or supplementation) has been around for a long time. Yet most prenatal vitamins have much more than that: most have 800 mcg listed, some have over 1,000 mcg. Where did this doubling come from? I do not know but I suspect it came from the general idea that if some is good, more is better. I also suspect that by increasing the amount of certain nutrients, you can add the label “Prenatal Vitamin” and use this as a marketing tool.
To make things more complicated, the amount listed on the label, may not be what is actually in the tablet. One independent lab found that of the prenatal vitamins they tested, 20% had more folic acid than listed, and the average amount of folic acid in tested prenatal vitamins was 1024 mcg per tablet. That is above the established Tolerable Upper Limit (TUL) of folic acid for humans. For both pregnant and lactating women, the TUL is 800-1,000 mcg of folic acid. This means that as soon as a pregnant woman ingests most prenatal vitamins, she has already reached the TUL, and that is before she has eaten any food!
Too much folate can do bad things like mask pernicious anemia, increase some cancers (pediatric leukemias are often treated with anti-folate drugs), and speed up cognitive decline in individuals with dementia. Since at least 2012, folic acid supplementation in pregnancy has been associated with increased risk of autism. And now, out of Boston, comes a report that excessive folate levels in the mother’s blood can double her child’s risk of developing autism. Having excessive levels of Vit B12 tripled the risk. Having excessive levels of both folate and Vit B12 increased the risk even more: with both levels high, the risk of the child developing autism was almost 18 times higher. Ugh. That is huge!
In the Boston Cohort Study, 1,391 mother-child pairs were recruited and studied from 1998 to 2013. Maternal blood levels of folate, Vit B12 and Homocysteine were drawn from between one and three days after birth. Prenatal history of multivitamin use was taken. Maternal genotype of MTHFR was determined. The babies’ medical records were then tracked for diagnosis of Autism Spectrum Diagnosis (ASD).
And the results were interesting: Having increased homocysteine levels, or having a maternal MTHFR mutation did not increase risk of the child being diagnosed with ASD. The majority of women took multivitamins at least occasionally during their pregnancy. Taking a multivitamin 3 to 5 times a week was associated with a decreased risk of the child being diagnosed with ASD. But having elevated maternal blood levels of folate, and/or Vit B12 greatly increased the risk of the child being diagnosed with ASD. In this study, 1 in 10 women had excessive levels of folate and/or Vit B12 in their blood: 10% of the women had excessive levels.
What is an excessive level? This study used a cut off of >59 nmol/L for folate, a level of >600 pmol/L for Vit B12. The World Health Organization (WHO) suggests that >45.3 nmol/L of folate is excessive for pregnancy.
Can I as a midwife find out if my clients have such excessive levels of folate (or both folate and Vit B12)? I cannot. Commercial labs have much lower cutoffs for ‘excessive’ levels than either WHO or the Boston Birth Cohort. The lab I generally use, BioReference Laboratories Inc. (BRLI) has a top result of ‘greater than 24’.
Recently I drew a client’s blood to test her folate level. This client is pregnant, she is a medical professional, we were planning to do a standard prenatal blood test, and the Boston study had just been released. My client was curious to see what her blood folate level was. So I added this to the test requisition. Later, when the result was available, I found that I could not give her an adequate answer. I could only tell her that the folate level in her blood was something above 24. I do not know if it is simply 25 (well below both the WHO and Boston cutoffs) or 250 (crazy high). I have no way of knowing. She decided to continue eating a healthy, balanced diet and to immediately stop taking her prenatal vitamin.
For years, decades really, I have suggested that clients avoid prenatal vitamins, always keep a regular ole’ multivit in their cupboards and that they take one of those on days when their diet is not up to snuff. I repeat this spiel almost daily: “If you are eating 5-10 servings of fruits and vegetables every day, you probably don’t need a supplement, However, if you are going to bed and you realize that the only veggie you had all day was a thin piece of sad looking lettuce, please grab that vitamin.” Also, I strongly suggest that anyone at risk of getting pregnant (the person has a uterus, there is possible exposure to semen, is of childbearing age), take a multivitamin daily to reduce the risk of serious neural tube defects. Of course, women that have a personal or family history of neural tube defects need to be consulted individually: they may do best with 1-4 grams of folic acid daily prior to pregnancy and for the first 12 weeks after conceiving.
The information from this new study is not changing my basic message: eat a healthy diet, supplement that diet with vitamins occasionally. But it is changing how loudly I will say it because MORE IS NOT ALWAYS BETTER, EVEN WITH FOLIC ACID.
K. Michelle Doyle
May all babies be born into loving hands
More food for thought:
The following charts were created to illustrate that if a woman that eats the recommended diet, and takes a over the counter prenatal vitamin containing 800 mcg of folic acid/folate would be well over the 800-1,000 mcg Tolerable Upper Limit for folate.
(And, now repeat after me: more is not always better.)
Here are some examples of foods and their Vit B12 and Folate content:
|1 oz cheese
|3 oz tofu
|| 2 (34%)
|Peanut butter, 1 Tsp
|Cereal, 1 cup
|Milk, 1 cup
|Yogurt, 1 cup
|Beef, 1 oz
|Bread, 1 ounce
|Rice, 1/2 cup
|Pasta, 1/2 cup
|Spinach, 1 cup
|Asparagus 1/2 cup
|Lettuce, 1 cup
|Broccoli, 1/2 cup
|Orange, 1 cup
|Banana, 1/2 cup
|Blueberries, 1/2 cup
Here is the amount of Vit B12 and Folate/Folic Acid in a sample diet based on the dietary guidelines and the nutrient levels listed above:
|Vegetables, 3 cups
|Fruit, 2 cups
|Grains, 8 ounces
|Dairy, 3 cups
|Protein, 6.5 oz
So…. A woman that eats the recommended diet, and takes a over the counter prenatal vitamin containing 800 mcg of folic acid/folate would be well over the 800-1,000 mcg Tolerable Upper Limit for folate. (And, now repeat after me: more is not always better.)