MTHFR, Hashimoto’s, and Nutrients

The MTHFR gene instructs the body to produce an enzyme called methylenetetrahydrofolate reductase. This enzyme helps process amino acids, the building blocks of protein. MTHFR helps metabolize one form of the vitamin folate (also called vitamin B9) into another. 


mthfr gene


Methylated folate is needed for the process that converts homocysteine ​​to methionine, both amino acids. Methionine helps the body make proteins and other essential compounds.

Understanding MTHFR gene mutation 

We receive two copies of the MTHFR gene from each parent. This means that we can get two copies of the "normal" MTHFR gene, one "normal" copy and one copy with the genetic variant, or both copies with the genetic variant.  

Individuals with one or two copies of the genetic variation and low MTHFR enzyme activity may exhibit elevated homocysteine ​​levels, which have been linked to inflammation, heart disease, pregnancy complications, and even miscarriage. 

down syndrome

It has also been linked to higher rates of Down syndrome and birth defects in the offspring of people with variation in the MTHFR gene, as well as to other problems that can manifest later in life, such as depression, increased risk of blood clots, and risk of some tumors.

One of the most important things to note is that this genetic variation also prevents people from properly methylating, which is one of the body's most important detoxification processes, helping them get rid of toxins. Altered methylation can lead to an impaired ability to eliminate certain toxins, such as mercury and arsenic, and can lead to estrogen dominance. 

Symptoms such as brain fog, multiple chemical sensitivities, depression, irritability, and anxiety are linked to altered methylation. Because these symptoms are all too common in Hashimoto, I developed a liver support protocol to support the methylation pathways.

brain fog

Studies have shown that another possible consequence of this genetic variation is sensitivity to certain anesthetics, such as nitrous oxide, which is commonly used for dental surgeries. If you are about to have surgery and have the MTHFR gene variation, you can locate and print the following articles so that your surgeon and anesthetist can share this information with them and research other treatment options for anesthesia.

Genetic effects on nutrient extraction 

Genetic variation may also play a role in vitamin deficiency. In particular, high levels of homocysteine, often caused by variation in the MTHFR gene, have been linked to nutritional deficiencies of vitamins B2, B6, B9 (folate), and B12.

It may seem reasonable to take a dietary supplement to correct a folate deficiency, but not all sources of vitamin B9 are created equal. Although vitamin B9 occurs naturally in foods such as folate, it can also be found as folic acid, a manufactured version of folate found in most budget multivitamins and often added to processed foods.


Unfortunately, folic acid can be very problematic for those with the MTHFR gene variation, as they may struggle to process this form of folate. Some professionals claim that this type of synthetic folate can even cause a buildup in the body, leading to toxicity.

Correlation between the genetic variation and Hashimoto's

Does everyone with Hashimoto have this variation and does Hashimoto make it worse?" The answer is no! 

A recent study found that polymorphisms, i.e. genetic variations that can lead to abnormal expressions – are as common in autoimmune thyroid disease as they are in the general population. 

Additionally, the authors concluded that the severity of autoimmune thyroid disease (AITD) is not correlated with whether or not one has this genetic variation.

In other words, the likelihood of having one or both MTHFR polymorphisms, as well as the frequency of variants (alleles) of the MTHFR gene, were not more common in people with autoimmune thyroid disease than in affected individuals.

Nevertheless, the MTHFR gene variation occurs more frequently in patients with hypothyroidism.

Testing for the MTHFR gene and high homocysteine levels

You can do genetic testing to find out if you have this gene as well as high levels of homocysteine. It is important to test for both homocysteine ​​levels and the MTHFR gene variation because although you may not have the gene that affects methylation pathways, you can still have elevated homocysteine ​​levels. , which tells us the level of inflammation in our body. 


High levels of homocysteine ​​can also indicate a lack of B vitamins. While higher homocysteine ​​levels have been linked to many health complications, low homocysteine ​​levels can also be problematic and have been linked to peripheral neuropathy (often felt as tingling in the hands and arms) and an impaired ability to make glutathione, an antioxidant that causes inflammation in the body reduced body. Low levels of glutathione have been correlated with Hashimoto and heavy metal toxicity.

Elevated homocysteine, whether or not you have the MTHFR gene variation, can indicate inflammation in the body. While people with high homocysteine ​​levels may benefit from diet and supplementation (especially if the increase was caused by inflammatory foods and nutritional deficiencies), other reasons for the inflammation should also be explored with the doctor.

The MTHFR variation doesn't necessarily mean a person is predisposed to many health conditions and symptoms, and a greater number of variations don’t always mean the person will have more symptoms.

There are several factors that determine the expression of these genes, such as the interaction of other genes, life choices, and interventions.

Symptoms associated with under or over methylation 

How can you tell that you may be experiencing impaired methylation? Here are some symptoms of undermethylation to look out for:

  • Elevated homocysteine levels
  • Depression
  • Irritability
  • Anxiety
  • Multiple miscarriages
  • Multiple chemical sensitivities
  • Sensitivity to anesthetics
  • The red face that lasts after exercising
  • Allergies
  • Being prone to addiction
  • High libido
  • Obsessive-compulsive disorder (OCD)
  • Low pain threshold
  • Headaches/migraines
  • Digestive problems (such as IBS)
  • Brain fog (especially after protein-rich meals)
  • Insomnia
  • High estrogen levels
  • Low energy/fatigue
  • Muscle pain
  • Low levels of neurotransmitters (dopamine, norepinephrine, and serotonin)



While under-methylation is more common with the MTHFR gene, over-methylation may instead be the case. This can affect the thyroid and adrenal glands and cause other health problems. Over-methylation can also occur if people start taking too potent methylation support supplements.

Symptoms of overmethylation can include:

  • Restless legs/pacing
  • Hyperactivity
  • High pain tolerance
  • Histamine intolerance
  • Sleep disorders
  • Panic disorders
  • Paranoia
  • Insomnia
  • Low libido
  • ADHD
  • Low motivation
  • Depression
  • Anxiety
  • High levels of neurotransmitters (dopamine, norepinephrine, and serotonin)
  • A high copper-to-zinc ratio

In general, under-methylation leads to symptoms more akin to depression and sluggishness, while over-methylation is usually associated with symptoms such as hyperactivity and anxiety. But it's not always easy to tell what's going on without testing it.

For this reason, it is important to follow a doctor's instructions and use supplements with caution.


Some people have a genetic variation that can affect their detoxification abilities, affect the absorption of certain B vitamins, and contribute to their symptoms. Nevertheless, knowledge leads to empowerment. Again, while we cannot change our genes, we absolutely can change their expression!

You can support your methylation pathways with dietary interventions and supplements. To start your journey to wellness, I recommend testing your homocysteine ​​levels and seeing if you have markers of MTHFR gene variation. If you do, supporting your methylation pathways with supplements may help reduce some of the symptoms you experience.