MTHFR variant and folic acid: What you need to know

July 8, 2020

MTHFR stands for methylenetetrahydrofolate reductase. It’s an enzyme (protein) that helps your body break down and use folate. One MTHFR variant (called MTHFRTT or CT genotype) is a change in your body’s MTHFR gene that makes you use folate more slowly than usual. MTHFR variants are inherited (passed from parents to children) through genes.

Folate is the natural form of folic acid. Folic acid is a B vitamin. Every cell in your body needs it for healthy growth and development. Folic acid is the manmade form of folate that is in fortified foods and vitamin supplements. Fortified means a food has folic acid added to it.

If you have an MTHFR variant, taking 400 mcg of folic acid every day before and during early pregnancy can help prevent neural tube defects (NTDs) in your baby. NTDs are birth defects of the brain, spine and spinal cord.

How much folic acid do I need?

Making sure you have enough folate in your blood to help prevent an NTD depends on:

  • The amount of folic acid you get each day from foods, vitamins or supplements fortified with folic acid
  • How long you get folic acid before becoming pregnant

The Centers for Disease Control and Prevention (also called CDC) recommends that all women take 400 mcg of folic acid every day before and during early pregnancy.

You may have heard you should take other types of folate, like 5-MTHF, if you have an MTHFR variant. However, folic acid is the only type of folate shown to help prevent NTDs.  Getting 400 mcg of folic acid each day before and during early pregnancy can reduce the risk of having a baby with NTDs by up to 85 percent.  Do not take a vitamin supplement with more than 400 mcg of folic acid each day, unless it is recommended by your provider. A provider may recommend you to take more than 400 mcg if you have other health conditions, or if you already had a baby with a neural tube defect.

If you know you have an MTHFR variant or you think it runs in your family, talk to your provider.