MTHF Folate vs. Folic Acid: What’s Better for Prenatal Vitamins?

Learn about the distinctions between the different types of folate and how to choose which one is best for you.

By Dr. Liz Kane

Folate, folic acid, and MTHF folate, oh my!

A good prenatal vitamin should be one of the first purchases you make after you decide you want to get pregnant. One of the key ingredients in a prenatal vitamin is folate, but not all forms of folate in vitamins are equal. To help you understand the differences, we’re going to walk you through the important scientific details, starting with some keywords:

• Folate is a B vitamin. It is an umbrella term for a class of chemical compounds found naturally in foods⁠, food folates, and ones made artificially, synthetic folates.
• Folic acid is a synthetic form of folate made in a laboratory. It’s found in vitamins, and it is also used in fortification of some processed foods.
• L-methylfolate, abbreviated MTHF folate, is a food folate that can also be found in prenatal vitamins. It’s a bit confusing, but MTHF folate can go by many names, such as levomefolic acid, L-5-MTHF, L-5-methyltetrahydrofolate, and (6S)-5-methyltetrahydrofolate, (6S)-5-MTHF. Theyare all the same kind of folate.

Folate and its role in pregnancy

The most important role folate plays in a prenatal vitamin is the prevention of neural tube defects (NTDs) in the baby. NTDs are deformities of the neural tube, which is the embryonic precursor to the brain and spine. During a healthy pregnancy, the tube will seal itself off between three and four weeks of fetal development. In the case of an NTD, the tube doesn’t fully close, leading to devastating and life-threatening conditions like spina bifida.

Research studies have shown that folate supplementation reduces the incidence of NTDs significantly. The results of these studies prompted the United States government to institute a folic acid food fortification program in 1998 so that all women of childbearing age would consume extra folate through their diet. Since the implementation of food fortification, NTDs have decreased in the US by 35%. We don’t yet fully understand how folate supplementation lowers NTD risk, but we know that it involves decreasing levels of homocysteine, an amino acid which is also tied to a higher risk of heart disease and stroke.

Besides helping to prevent NTDs, folate is also essential for creating new DNA, proteins, and red blood cells, the cells that transport oxygen throughout the body.

MTHF folate is the best choice

To choose the most beneficial form of folate supplementation, you’ll want to consider how your body absorbs and utilizes MTHF folate versus folic acid. While all folates are absorbed in the intestine, there are distinctions in the processing of each type.

MTHF folate can be utilized immediately by your body. This means it has high bioavailability, which is a measure of how well a drug can be absorbed by the body. In fact, MTHF folate is the most common folate found in the human body.

In contrast, folic acid cannot directly be used by the body. It must be converted by two chemical reactions into another folate that your body can metabolize — specifically, MTHF folate. That’s right, folic acid must first be converted into MTHF folate for your body to use it. Supplemental folic acid also carries the risk of masking symptoms of B12 deficiency, which can lead to anemia, one of the very risks you’re trying to prevent by taking a prenatal vitamin.

The MTHFR gene

There’s another risk of folic acid to consider: based on your genetics, you could be impaired in your ability to convert folic acid into MTHF folate. Your body uses an enzyme (a protein that facilities a chemical reaction) called methylenetetrahydrofolate reductase (MTHFR) in one of the steps to convert folic acid to MTHF folate. Up to 25% of the population has a variant of the MTHFR gene (MTHFR 677TT) that significantly impairs their ability to metabolize folic acid. Individuals with this MTHFR variation are also at a higher risk of having a child with neural tube defects. The research is still preliminary, but people with this MTHFR variant would likely benefit from MTHF supplementation over folic acid as well.

How much folate?

Most health professionals recommend a daily intake of 400 micrograms of folate one to three months before conception and 600 micrograms of folate for the duration of pregnancy. While it’s theoretically possible to consume this much from food, absorption of food folates is variable and not guaranteed (particularly since a significant amount of folate supplementation in food takes the less-efficient form of folic acid). To ensure you get the folate you need, it’s recommended that all women planning a pregnancy take supplemental folate. Taking a prenatal vitamin with MTHF folate as soon as you even consider trying to conceive (or just as soon as you find out you’re pregnant) can provide this nutritional safety net.

Rely on your vitamins

We know these details and decisions feel stressful and high stakes, and they are: this is your baby’s development, and it’s normal to want to cover all your bases and do everything you can. It’s a way of feeling more in control in an unpredictable, sometimes-scary time in your life.

We encourage you, though, to try and consider your choice of prenatal vitamins as a means to provide yourself with support for your emotional well-being, as well as your physical health. You can’t control whether or not you get severe morning sickness that keeps you from eating a balanced diet. You certainly can’t control your genes. However, choosing a prenatal vitamin with MTHF folate means optimizing the likelihood that your vitamin will support your health — and your baby’s — in the best way possible.

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