What is MTHFR?

MTHFR is an enzyme that adds a methyl group to folate to make the active form called Methylfolate also known as 5-MTHF the body can use. The MTHFR gene produces this enzyme that is necessary for properly using vitamin B9 (the other name of Folate).

This enzyme will also play an important role for converting homocysteine into methionine, which the body needs for proper metabolism and muscle growth and which is needed for glutathione creation  (our major antioxidant). The process of methylation also involves the enzyme from the MTHFR gene, so those with a mutation may have trouble effectively eliminating toxins from the body.

The MTHFR gene provides instructions for making an enzyme called MethyleneTetraHydroFolate Reductase. This enzyme plays a role in processing amino acids, the building blocks of proteins. Methylenetetrahydrofolate reductase is important for a chemical reaction involving forms of the vitamin folate (also called vitamin B9). Specifically, this enzyme converts a molecule called 5,10-methylenetetrahydrofolate to a molecule called 5-methyltetrahydrofolate. This reaction is required for the multistep process that recycles the amino acid homocysteine to another amino acid, methionine. The body uses methionine to make proteins and other important compounds such as SAMe (S-Adenosyl-Methionine)

Contrary to how it looks, “MTHFR” is not an abbreviation for a curse word, but a shortened form of methylenetetrahydrofolate reductase…

It is important to give the MTHFR enzyme the right fuel: Folate and avoid Folic acid. Look at my other post: folic acid vs. folate. To optimize this enzyme function you need to avoid synthetic folic acid in supplements and foods.

Those of us with a MTHFR gene mutation have a highly reduced ability to convert folic acid or even folate into a usable form. Research estimates that as much as half of the population may have an MTHFR gene mutation (most frequently encountered in Hispanic and Italian ethnicities), though there are many variations of the mutation, depending on how the gene was passed down from the parents.

Additional Reading

If you are new to MTHFR and feel overwhelmed like I did, here are some great resources for more reading:



The Role of L-methylfolate in Depressive Disorders: Commentary


L-methylfolate, Methylcobalamin, and N-acetylcysteine in the Treatment of Alzheimer’s Disease-Related Cognitive Decline