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When I got my first job fifteen years ago at a premier nutritional medical laboratory, all the talk of “methylation” had me confused. What’s so special about methylation? There’s a methyl group (-CH3) on every organic compound! So what if it’s being transferred around?

Well, I came to realize that our lives depend on methylation.


Healthy methylation is an indicator of good nutrition. Methylation requires a number of important vitamins and amino acids. The methylation vitamin “poster child” is folate, but it doesn’t work alone. Folate teams up with vitamin B6, vitamin B12, betaine, choline, methionine and other nutrients to do methylation, or pass around one-carbon methyl groups.


Methylation is a small biochemical reaction with paramount consequences.

“Methylation” is more correctly referred to by scientists as, “one carbon metabolism.”


It is absolutely critical for some very basic functions:

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  • Nucleic acid synthesis (making the building blocks of DNA)
  • Blood cell production
  • DNA methylation (turning on/off genes)
  • Making neurotransmitters
  • Homocysteine metabolism
  • Protein methylation
  • Phase II detoxification


Inadequate methylation capacity can lead to birth defects, depression, poor brain function, heart disease, and cancer. According to a 2019 paper, one in five Americans is low in folate or approximately 20% of the population.1 However, Black men and women have even more folate insufficiency, coming to almost 39%!

On the other hand, certain groups may be getting too much folate or folic acid. Too much folic acid might be a problem when adding fortified foods on top of supplements in people at risk of cancer. People over 60 years old who take supplements had twice as much folate in their blood as their non-supplementing counterparts.1 See my first blog on folate and why it’s so important to get the amount that is just right.


Folate tests will help you figure out if you have enough (or too much) of this critical vitamin.


Who Might Benefit from a Folate Test?


  • Autism

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  • Alcoholism
  • Brain atrophy, or the loss of brain cells, due to aging or illness
  • Cancers
    • Leukemia, lymphoma, colorectal, breast, and prostate cancers
  • Cardiovascular disease
    • High blood pressure, heart attack, or stroke
  • Celiac disease
  • Cognitive decline
  • Depression
  • High folate supplementation (e.g., taking Deplin)

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  • History of megaloblastic anemia
  • Infertility/miscarriage
  • Inflammatory bowel disease (Crohn’s or ulcerative colitis)
  • Intestinal malabsorption
  • Preconception care
  • Schizophrenia
  • Suicidal tendencies
  • Prescription drug use
    • Phenytoin, primidone (anticonvulsants)
    • Sulfasalazine (inflammatory bowel disease)
    • Triamterene (diuretic)
    • Metformin (type 2 diabetes)
    • Methotrexate (rheumatoid arthritis)



When There Isn’t Enough Folate, The Body Goes Into a Downward Spiral

When a person’s body runs out of enough folate to do methylation, it will likely affect tissues and cells first (this is where functional tests of folate come in). Once folate deficiency is serious enough to affect the blood, the levels of folate will go low in a person’s blood plasma. In the face of low folate, blood homocysteine will increase and a person’s red cell folate will finally decrease.2

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Without enough folate, the bone marrow won’t be able to make healthy blood cells. Megaloblastic anemia occurs when red blood cells are unusually large, deformed, and immature. People can have this type of “folate deficiency anemia” for years and they may have no obvious symptoms. However, others will experience symptoms such as fatigue, paleness, shortness of breath, lightheadedness, dizziness, or a fast or irregular heartbeat. This type of anemia can be detected on a standard blood test at your doctor’s office called a complete blood count (CBC).

Because moving around methyl groups is such a critical yet basic biochemical process, various tests can be used to help get a comprehensive picture of a patient’s methylation capacity. Integrative and functional medicine clinicians might use multiple markers in blood and urine to make sure all methylation systems are “go.”

Standard Folate Lab Tests

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  • Serum folate- this is considered by nutrition scientists to be the earliest blood indicator of altered folate intake. This level reflects recent folic acid consumption and dietary folates. Food folates don’t increase this level as much as folic acid from supplements or fortified foods.2
  • Plasma homocysteine– an amino acid that is a sensitive functional marker of folate status. Homocysteine is a good methylation marker and can become elevated when there is need for folate, vitamin B6, and/or vitamin B12. Homocysteine can increase in heart disease.
  • Red blood cell folate or RBC folate. This is “widely considered to be the most robust biomarker of long-term status” among nutrition scientists and it is moderately correlated with folate intake. Since the folate content of red cells is fixed when making blood cells in the bone marrow, RBC folate is indicative of folate stores and long-term status of ~4 months. According to some sources, this marker goes higher with folic acid supplements than with food folates.2



Integrative and Functional Tests that Assess Folate and Methylation Capacity

Just because standard folate lab tests are normal does NOT mean a person has adequate folate at the tissue level. This has been noted in the gums, which depend on folate. And in this incredible folate review paper, nutrition scientists point out that having a normal folate blood test does not mean that a person has optimal folate levels. In fact, they may still have health problems due to low folate.


“…meeting a particular criterion or prevalence estimate of folate deficiency in a given population (e.g.,>5% with a folate biomarker value falling outside a cutoff point indicative of deficiency) does not mean that folate status is optimal in the ‘‘nondeficient’’ portion of the population. In fact, in many settings, although folate deficiency may be relatively rare, suboptimal folate status with accompanying implications for health may be common.”


That’s why functional lab tests are important, too. They can help detect a problem early, before standard lab tests show problems, before folate goes low in the blood, and before symptoms crop up.


Find out how your body processes folate with this MTHFR gene test  Order MTHFR Test

or get your homocysteine, RBC folate, and other blood tests done. Order Methylation with CBC Test


Here are the Integrative and Functional Folate Tests You Need To Know About:

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  • 5-Methyltetrahydrofolate (5MTHF or methyl-folate)the main form of folate found in blood.
  • Folinic acid (5-formyl tetrahydryl folate) and tetrahydrofolate are active forms of folate that the body uses rapidly in metabolism. They can be measured in blood.
  • UMFA – Unmetabolized folic acid (UMFA) blood levels can show if a patient is able to metabolize folic acid.
  • Methylenetetrahydrofolate reductase (MTHFR)- a genetic test about the MTHFR enzyme, which is important in producing methyl-folate and recycling homocysteine. This gene may increase risks of certain diseases and may mean that the best form of folate for you to take is methyl-folate or folinic acid. In the US, about 25% of Hispanics and 10-15% of Whites have two copies of the C677T variant.
  • Catechol-O-methyltransferase (COMT)- a genetic test of COMT, an enzyme that helps degrade neurotransmitters via methylation.
  • Amino acids. Amino acids are precursors for methylation and many aminos undergo methylation during metabolism. Best measured in plasma, methionine is the precursor to homocysteine while glycine and serine are both methyl donors.
  • Estrogen methylation ratio (2OHE1:2OMeE1)- measures a person’s ability to methylate estrogens. The 2OHE1/2OMeE1 ratio shows if a patient can turn 2-hydroxyestrone into 2-methoxyestrone via methylation.
  • Urinary organic acids
    • Formiminoglutamate (FIGLU)- functional marker of folate need.
    • Methylmalonate (MMA)- functional marker of vitamin B12 need.
    • Xanthurenate – functional marker of vitamin B6 need.

Future Possibilities for Folate Lab Tests

  • Para-aminobenzoylglutamate and para-acetamidobenzoylglutamate– these are the oxidative break down products of folate and give information about folate status and turnover. This seems like a reliable test because total urinary excretion is associated with serum, RBC, and dietary folate.2,3 This is not currently available at a commercial laboratory to my knowledge, but has been in the past.
  • DNA cytosine methylation– this process is compromised when folate levels are low. This marker decreases with poor blood folate and high homocysteine.
  • Uracil misincorporation into DNA– an enzyme in DNA synthesis requires adequate folate and this change in the structure of DNA may be a specific marker of folate deficiency.
  • Micronuclei– when too much uracil is built into DNA, it can lead to chromosomes that form micronuclei. The presence of micronuclei (abnormally small nucleus-like cell structures) can indicate low folate. Micronuclei are associated with low folate intake, low RBC folate, and high homocysteine.2


Always remember: A single test doesn’t tell us everything. One test that evaluates a methylation marker may not be enough to determine that all biochemical processes are running smoothly. While homocysteine is a widely recognized methylation marker, other markers can help view a patient’s methylation capacity from different angles.

If your folate test is lower than the normal range, you will need to increase dietary folate and supplements.

Foods Rich in Folate

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  • Asparagus
  • Avocado
  • Beans
  • Beets
  • Broccoli
  • Brussel sprouts
  • Citrus fruits
  • Dark green leafy vegetables
  • Eggs
  • Lentils
  • Nuts and seeds

Common Supplements to Enhance Methylation

  • Folate (in the appropriate form, as testing indicates)
  • Vitamin B12
  • Vitamin B6
  • Choline
  • S-adenosylmethionine (SAMe)
  • Betaine or trimethylglycine (TMG)


The Best Tests for Figuring Out Your Folate Level

While it might appear to be an insignificant carbon and hydrogen group getting passed around between chemicals, methylation is actually the difference between life and death or health and disease. Patients struggling with infertility, autism, cancer, or stroke may all greatly benefit from folate tests and methylation tests.

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No one test is enough to make definitive conclusions about a patient’s methylation capacity. RBC folate and homocysteine can be used together as convenient routine folate and methylation tests. Other tests can help view a patient’s methylation capacity from different angles. The genetic test, MTHFR, and folate tests such as 5-MTHF or UMFA can help figure out a person’s genetics and help to pick the best form of folate to take. Other functional tests can uncover early folate need or methylation difficulty; these include FIGLU, MMA, amino acids, and estrogen metabolism. 

~~~~~This blog is dedicated to my favorite nutritional biochemist and clinical laboratory teacher, Dr. Richard Lord, and his lovely wife, Gwen.~~~~


  1. Pfeiffer CM, Sternberg MR, Zhang M, et al. Folate status in the US population 20 y after the introduction of folic acid fortification. Am J Clin Nutr. 2019;110(5):1088-1097.
  2. Bailey LB, Stover PJ, McNulty H, et al. Biomarkers of Nutrition for Development-Folate Review. J Nutr. 2015;145(7):1636s-1680s.
  3. Niesser M, Demmelmair H, Weith T, et al. Folate catabolites in spot urine as non-invasive biomarkers of folate status during habitual intake and folic acid supplementation. PLoS ONE. 2013;8(2):e56194.


Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, MS, is a researcher, author, educator, and laboratory consultant. She studied medicinal plants in the rain forests of Panama as a Fulbright Scholar and then launched a career in science and natural medicine. Early on, she studied ethnobotany, ethnopharmacology, and drug discovery at the University of Georgia and AptoTec, Inc. She joined innovators at Metametrix Clinical Laboratory as a medical education consultant helping clinicians use integrative and functional laboratory results in clinical practice. She owns Health First Consulting, LLC, a medical communications company with the mission to improve human health using the written word. Ms. Nelson-Dooley is an oral microbiome expert and author of Heal Your Oral Microbiome. She was a contributing author in Laboratory Evaluations for Integrative and Functional Medicine and Case Studies in Integrative and Functional Medicine. She has published case studies, book chapters, and journal articles about the oral microbiome, natural medicine, nutrition, laboratory testing, obesity, and osteoporosis.