The MTHFR Gene and Why It Matters To Hypothyroidism And Thyroid Health

Ready to learn more? This post shines the spotlight on the MTHFR gene and WHY it matters to thyroid function and health and the issue of an underactive thyroid gland.

Firstly, let’s look at what the MTHFR gene does.

The methylenetetrahydrofolate reductase gene, or MTHFR gene for short, contains the genetic code to produce the MTHFR enzyme. This is an important life-sustaining enzyme that sparks activity within all cells. This enzyme also plays an integral role in activating folate.

Here’s 3 Things You Need to Know About The MTHFR Enzyme and hypothyroidism

Research shows a faulty MTHFR gene that exhibits various mthfr gene polymorphisms can impact your thyroid with various thyroid problems and overall well-being. Here are three things you need to know in the context of thyroid disorders.

#1 The MTHFR Enzyme Helps The Body Utilize Folate

Folate, or vitamin B9, is an incredibly important micronutrient that supports day-to-day functioning of the body. You will see the terms folate, and folic acid used interchangeably but they are NOT the same.

Let me explain more…

  • Folic acid is the name given to the synthetic version of folate. Folic acid is not biologically active until it’s been converted to methyl folate, the body’s most active form of folate.
  • For those diagnosed with a faulty MTHFR gene they may have problems converting folic acid to methylfolate. Supplementing with methyl folate bypasses the folic acid metabolic cycle. This improves folate absorption and minimizes potential problems associated with a build up of unmetabolized folic acid.

#2 The MTHFR Enzyme Assists Proper Breakdown of Homocysteine

A faulty MTHFR gene is linked to elevated homocysteine. And that’s problematic as studies clearly show too much homocysteine is a risk factor for neurological decline, and cardiovascular disease.

Here’s what you can do about it…

Supplementing with a combination of vitamin B6, B12, and methyl folate is usually recommended to lower homocysteine.

These three nutrients team up to support methylation which in turn helps keep homocysteine in check. Functional medicine experts usually prescribe the active forms of these vitamins. That is, methyl folate, methyl B12, and vitamin B6 as pyridoxal 5-phosphate (P5P).

# 3 MTHFR and Methylation

MTHFR gene defects are associated with poor methylation, the key biochemical processes that keep your cells healthy. Proper methylation is therefore critical to many aspects of health including;

  • maintaining an optimistic mental outlook
  • positive gene regulation
  • detoxification of environmental toxins
  • keeping homocysteine in check
  • regulating histamine levels
  • maintaining healthy immune function
  • healthy aging

Poor methylation can lead to a buildup of toxins, mood changes, allergies, and poor immunity, including a decreased ability to clear chronic infections. That’s cause for concern as chronic viral infections are frequently cited as a major factor in autoimmune thyroid diseases.

Once you understand the link with optimal methylation you can fully appreciate WHY the MTHFR gene can affect your thyroid health.

The MTHFR Gene Mutation and Why It Matters To Thyroid Health

There’s increasing awareness that a faulty MTHFR gene can impact thyroid health.

So if you have been diagnosed with this particular genetic mutation here are three facts I would like you to know;

FACT #1: The B-Vitamins Support Proper Methylation

Methyl folate, pyridoxal 5-phosphate (P5P), and methyl B12 support optimal methylation activity.

This is an important point of difference, and it’s the reason supplements containing the active forms of these B-vitamins are popular with both practitioners, and consumers.

As a word of caution, you don’t need to take high doses of these nutrients to help support methylation pathyways. In fact, taking too much can cause an imbalance leading to over methylation issues.

What’s an optimal intake?

An optimal intake of folate, B6 and B12 depends on individual needs. Generally, everyday supplementation with 400 mcg of dietary folate equivalents (DFE) per day, and 400 mcg of methyl B12 is a good starting point.

Keep in mind your healthcare practitioner may make different recommendations based on your individual needs.

FACT #2: Your Folate Status Is Important For Healthy Red Blood Cell Production

Low folate due to a genetic block can lead to megaloblastic anemia, a condition in which the body produces unusually large, and abnormally shaped red blood cells.

You may already know your red blood cells transport oxygen, and nutrients throughout your body. When red blood cells aren’t produced properly it gives rise to symptoms such as ongoing fatigue, weakness, shortness of breath, a pale pallor, and mood changes.

You can learn more about choosing the best folate supplement here: How To Choose The Best Form of Folate {A Naturopath Explains}

FACT #3: The MTHFR Genetic Variant is Linked to Raised Homocysteine

If you have been diagnosed with a MTHFR genetic mutation it’s wise to check homocysteine. Given that thyroid dysfunction is associated with heart, and cognitive health issues your medical practitioner will likely perform further testing when homocysteine is raised.

Keep In Mind Your Genetic Makeup Is Not Hardwired

One of the biggest things I’ve learned over recent years is that our genetic makeup is not hardwired.

Let me explain more…

The emerging science of epigentics tells us that we have the power to either switch on, or switch off gene variants.

In effect, science is telling us that environmental factors such as diet, nutrition, pollution, stress and aging have a major influence on gene expression. It’s further proof a nutritious diet, targeted nutritional supplements, and healthy lifestyle practices are especially powerful tools that we can use to influence our well-being…right down to the genetic level.

Note: This information should not be used as a substitute for treatment, or advice from your qualified healthcare practitioner. Consult your qualified healthcare practitioner before beginning any new nutritional product, diet, exercise, or health program as they are best suited to make recommendations to support your overall health. This is especially important if you have a diagnosed medical condition, are taking prescription medication, or have a specific genetic polymorphism. Some natural health supplements are not recommended during pregnancy, or breast feeding due to a lack of scientific investigations.


Chen Y, Wang B, Yan S, Wang YG. Significant association between MTHFR C677T polymorphism and thyroid cancer risk: evidence from a meta-analysis. Genet Test Mol Biomarkers. 2014 Oct;18(10):695-702. Link

Fröhlich E, Wahl R. Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases. Frontiers in Immunology. 2017;8:521. doi:10.3389/fimmu.2017.00521. Link

Genetic and Rare Diseases Information Centre. MTHFR gene mutation. Link

Moll S, Varga EA. Homocysteine and MTHFR Mutations. Circulation. 2015 Jul 7;132(1):e6-9. Link

Wang B, Shao X, Song R, Xu D, Zhang J. The Emerging Role of Epigenetics in Autoimmune Thyroid Diseases. Frontiers in Immunology. 2017;8:396. Link

Yang YM, Zhang TT, Yuan L, Ren Y. The association between the C677T polymorphism in MTHFR gene and the risk of thyroid cancer: a meta-analysis. Eur Rev Med Pharmacol Sci. 2014;18(15):2097-101. Link

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