MTHFR – A Drop In The Ocean
It seems that everywhere we look these days, there is something being written or spoken about MTHFR or methylation.
Awareness is growing, and patients and practitioners are requesting a test for the MTHFR gene.
However, should we be relying on this as a single focus for treatment? Perhaps, we should be looking a little more broadly when it comes to supporting patients.
Firstly, let’s look at what we know about the human genome and the growing popularity in testing.
Thanks to the Human Genome Project (HGP) completed in 2003, we now know that the human genome is made of 3 billion base pairs. It is nearly the same (99.9%) in all people, and humans have an estimated 30,000 genes; we are yet to understand the function of more than half of them.
There can be variations to these base pairs. These are called single nucleotide polymorphisms (SNPs). A SNP is when a single nucleotide substitution of one base for another occurs in at least 1% of the population.
For example, a SNP may replace the nucleotide cytosine (C) with the nucleotide thymine (T) in a certain stretch of DNA. It is estimated that there are 10 million SNPs in the human genome! When a SNP occurs in a gene or in a regulatory region near a gene, it may play a role in the individual’s health by affecting the gene’s function.
Whilst the HGP helped to identify some genes that are linked to a speciic disease, we are still learning and research is being performed about the interaction between genes, nutrients and
The HGP has also meant an improvement in technology to now make genetic testing much more affordable and accessible. This has enabled the blossoming of testing providers to offer direct to patient or practitioner gene testing, and today individuals are increasingly discovering information about their SNPs.
What is MTHFR?
The methylenetetrahydrofolate reductase (MTHFR) gene provides instructions for making the enzyme methylenetetrahydrofolate reductase which converts 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. This is required to convert homocysteine to methionine, which the body uses to make proteins and other compounds in the body. More simply, it converts folate in your leafy greens to a more active form
of folate (methylfolate), to be used by the body.
This enzyme is a component of the one- carbon metabolism pathway, more commonly known as the methylation process.
What is methylation and why is it so important?
Methylation is involved in a number of important biochemical processes in the body, including gene expression, DNA and RNA synthesis, immune cell differentiation, neurotransmitter synthesis, histamine clearance, detoxiication, hormones, mitochondrial metabolism, phospholipid synthesis and myelination, and neural tube development.
It occurs in almost all cells in the body. Methylation involves the transfer of active methyl groups, and when utilised, S-adenosylmethionine (SAMe) is converted to S-adenosylhomocysteine (SAH), and then homocysteine.
The recycling of homocysteine to methionine can occur via two pathways – via methionine synthase conversion that requires the transfer of a methyl group from 5-methylenetetrahydrofolate (5-MTHF) by MTHFR or via betaine homocysteine methyltransferase (BHMT). During higher states of oxidative stress, homocysteine may be converted to cystathionine and then to taurine, glutathione or sulfate via the transulfuration pathway.
What conditions are associated with methylation?
Methylation is a dynamic process that requires balance. Many health issues are associated
with luctuations in the methylation process including ADHD, Alzheimer’s disease, anxiety, atherosclerosis, bipolar disorders, cancers, chemical sensitivities, chronic fatigue, cleft
palate, diabetes, depression, down syndrome, hypertension, fertility issues, insomnia, neural tube defects, Parkinson’s disease and schizophrenia.
What factors influence methylation and should they be considered?
Many research studies, on both animals and humans, suggest that methylation status can be impacted by nutrient availability including folate, vitamin B12, choline and vitamin B6. However, lifestyle, environmental factors
and other modulators can also impact overall methylation status. These include:
Environmental toxins may inluence methylation. These may include pesticides, car fumes, BPA, phthalates, persistant organic pollutants (POPs), mould toxins, and heavy metals such as arsenic, mercury, lead.
Some medications may inluence methylation. For example, bile acid sequestrants, chemotherapy medications and antacids can effect vitamin B12 levels.
Diet and nutrient levels
Some diets may not have suficient levels of nutrients to support methylation. A diet low in green leafy vegetables may mean low folate status, and similarly, a poorly managed vegetarian diet may be too low in vitamin B12. Other nutrient levels to consider include choline and vitamin B6.
A study suggested that consistent alcohol intake over six months impacted DNA methylation.
Gut health and the microbiome
Studies on mice and faecal transplants have suggested that the microbiome impacts methylation regulation. There are a number of folate-producing bacterial species that may impact methylation including Lactobacillus plantarum.
Various research looking at maternal behaviour in mice suggest an interaction between environment, stress response and methylation. Studies on humans suggest stress is associated with altered levels of DNA methylation.
Research suggests exercise has an impact on methylation, with a study on arterial stiffness showing that itness may have a protective effect on those with the MTHFR C677T polymorphism.
Inflammation or oxidative stress
Inlammatory responses caused by pathogens effect methylation.
Recent studies show that methylation occurs in mitochondria, which are inluenced by epigenetic changes and could impact health.10 A recent study on diabetic retinopathy suggested that regulation of mitochondrial DNA methylation has potential to restore mitochondrial homeostasis and inhibit the development of diabetic retinopathy.11 Therefore, it may be important to support mitochondrial function to assist with healthy methylation.
A study on the effects of epigenetics and
sleep found that sleep deprivation impacted methylation, which subsequently impacted brain function and mental health.12
There are a number of SNPs other than just MTHFR involved with the methylation process and these should also be considered.