When a person has the MTHFR mutation, they have trouble making the protein the body uses to digest folate. The U.S. Public Health Service recommends that persons able to get pregnant consume 400 mcg of folic acid, or folate, each day to prevent birth defects, causing significant concern for persons with the MTHFR mutation.
However, the CDC states that persons with the MTHFR mutation can still process folate. Additionally, the CDC states that folic acid is the only type of folate to prevent neural tube defects. This means the best multivitamin for a person with the MTHFR mutation contains folic acid.