What is MTHFR?

MTHFR is the name of an SNP, pronounced “snip”, which is a small building block of genetic information. Our MTHFR SNPs play a key role in our methylation cycle.

Lots of people say they “have” MTHFR but that in itself doesn’t really mean much.

Everyone “has” MTHFR because it is a key component to our methylation cycle.

Those who say they “have MTHFR” typically mean they have one of the known variations. These variations typically result in less than optimal methylation and impact the body’s ability to utilise certain nutrients, like B12 and B9-Folate. Poor methylation is known to be directly linked with a tremendous number of health conditions. But, whether you “have” MTHFR or not you can still have methylation issues and less than optimal MTHFR expression.

What is the Methylation Pathway?

The Methylation pathway is a series of genes that all impact the body’s methylation cycle.

If you have an optimal MTHFR SNP but have less than optimal SNPs elsewhere in the methylation pathway, or an excess of insults to your health, it can cause your MTHFR SNP to express negatively.

I think of it like a bridge, a suspension bridge depends on all the cables to be taut. If any have the wrong tension, or break, it can have a huge impact on the burden of the other cables and the overall stability of the bridge itself. A huge trauma can also damage the bridges structure and function.

Dr Ben Lynch calls this “Dirty Genes” because your environmental (nutritional, stress, lifestyle, trauma) factors can “dirty” the expression of our genes, causing them to manifest and express epigenetically in the least favourable way.

What is Methylation?

Methylation at its most simple is “just” the basic chemistry of adding a methyl- group. In the body this “just” adding a methyl group is enormously significant task, it plays a key role in a huge number of bodily functions and genetic expression, including the bodies ability to produce glutathione, mitochondrial function and DNA replication; as well as the formation and utilisation of many other important enzymes, hormones, neurotransmitters and amino acids are all dependent on this pathway.

Why Glutathione matters?

Glutathione is known as bodies “master” antioxidant. When the body isn’t producing enough glutathione it can’t detoxify optimally. This inability to detoxify increases the overall burden on the body’s organs and cells.

When the body can’t appropriately eliminate the environmental toxins it is exposed to it can make it more prone to adverse events from environmental toxins. Whether these exposures are new, chronic or acute, such as heavy metals, pesticides and many pharmaceuticals including medications, vaccines and chemotherapy. Modern day living exposes our bodies to a host of these exposures on a daily basis. This stretches our bodies abilities to manage and eliminate the toxins quick enough before our systems get overloaded with them, which in and of itself can dirty our genetic expression.

If you aren’t producing enough Glutathione, or eliminating toxins effectively (see: liver health 101), they can circulate in the body and can distribute into organs, and connective and adipose tissue for long term storage.

Why does methylation matter?

As a result of this key role methylation plays in the body its understandable that poor methylation is linked to numerous health conditions.

This includes but is not limited to: asthma/allergies, neurological disorders, cancers, chemical sensitivities, epilepsy, fibromyalgia, infertility and miscarriages, pre-eclampsia, postpartum depression and birth defects including anecephaly, cleft palates, congenital heart defects, hypospadias, spina bifida and oral ties.

Its important to note that when a baby is born with a midline defect like these, or sacral dimples and stork marks, it can be a sign of poor methylation during before and during gestation. This poor methylation can be due to a SNP variation or environmental influences dirtying maternal MTHFR expression. Just because you or your child do or do not have a specific known variation that inhibits optimal methylation it doesn’t mean you automatically have a clean or dirty expression.

Why diet and nutrition matter:

Both Folate (B9) and B12 are key to the optimal function of the Methylation cycle. But from the processing and modification of foods stripping grains of their bran and fortifying foods and supplements with synthetic forms, our bodies ability to utilise these foods nutritionally is seriously impaired.

Folic Acid (B9)?

Folic acid is the least bioavailable and most detrimental form of processed synthetic B9/folate you can get, most people can’t utilise it optimally and it can inhibit the body’s ability to absorb the more vital sources from our diet. So it is best to avoid supplements and foods fortified with Folic acid, unfortunately it is the most commonly used form because it is cheap and shelf stable, this does not mean it is the best for you. Folate, Folinic acid and Methyl-Folate are the more bioavailable forms available from foods and optimised supplements.

B12 (Cobalamin)?

Cyan-cobalamin is the B12 equivalent of folic acid. Its toxic in the body releasing small amounts of cyanide from its breakdown. It is poorly absorbed and blocks absorption pathways from utilising the more bioavailable forms. Methyl-, Adeno- and Hydroxy- cobalamin are all much better utilised by the body available from food and optimised supplements.


Because some are over- or under- methylators some do better with different forms of folate and B12. Those who are under-methylators can benefit with the methyl forms as they need the methyl donors, the methyl groups to add to the other compounds during methylation.Though other foods and supplements can contain methyl donors too. Those who are over-methylators can do better with the non-methyl folate, folinic acid, adeno-cobalamin and hydroxy-cobalamin forms.

Either way which ever you decide it can be important to start supplements slowly and not dismiss all forms if you seem to react to one.

Optimised forms are really important to optimise methylation, but they do depend on our current expression and unless you are under a practitioner who is informed on the matter or able to do OAT (organic acid testing) picking a form may be guess work to begin with. Though Dr Ben Lynch’s resources may be able to help you identify if your likely to be an over- or under- Methylator.


Seeking Health, Jarrow, Metabolics, Solgar , BioCare and Cytoplan are all trusted brands that have optimised and varied forms of Folate and B12. Their products are typically low in additional ingredients, deemed hypoallergenic and well tolerated by those why are prone to hypersensitivities.

Related resources:

Dr Ben Lynch:

Author of “Dirty Genes”

Host of the “Dirty Genes Summit”

Why you should care about Methylation:

Methylation pathway:

2 thoughts on “MTHFR 101

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