Anti-Aging Health Heart Health

The Most Important B Vitamin to take in it’s Correct Form

By Kim Crawford, M.D. Last updated: September 6, 2018
the most important b vitamin is found in many of these foods

What is the one most important B Vitamin?

All of the B vitamins are essential. However, I’m going to discuss the most important B vitamin to ingest in its proper form for your genetic profile. I’m talking about folate versus a “methylated” form of folate called 5-MTHF. Depending on your ethnic group, you may be at very high risk of having a health-harming methylation defect which I’ll explain shortly. When in doubt, it’s best to avoid folate-fortified foods and take this essential B vitamin as a 5-MTHF supplement.

What is Methylation and Why do we Care?

Methylation is an important biochemical process essential for the proper functioning of most of your body. It helps repair your DNA. It is necessary to help keep inflammation and detoxification in balance. Further, it controls homocysteine (an altered amino acid which damages blood vessels). The methylated form of folate is the most important B vitamin managing this process. Proper methylation also requires a healthy anti-inflammatory diet and absence of methylation-interfering pharmaceuticals. However, today we’re just focusing on your folate “situation.”

A breakdown of the methylation process in your body also puts you at higher risk for many medical conditions such as diabetes, cancer,  heart disease and more. I’ll discuss the potential problems thoroughly so you can decide if you need testing for an MTHFR deficiency.

MTHFR and folate metabolism

A deficiency of MTHFR is far more common than people, and even doctors think. What is MTHFR? MTHFR stands for methylenetetrahydrofolate reductase—an enzyme that activates folic acid by adding a methyl group to it.

The reason I listed heart disease above is that frequently an elevated homocysteine level is due to a genetic mutation (there are two) such that you are not methylating your folate rendering it useless for biochemical functions. In other words, you are not using folate because you cannot. Those with C677T MTHFR mutations do not process folic acid into methylfolate all that well.

Those with A1298C MTHFR mutations also have issues with biopterin. Biopterin is a product of the breakdown of the more complex tetrahydrobiopterin or BH4. Biopterin is a cofactor in the production of several necessary neurotransmitters in the body, including dopamine, serotonin, and epinephrine. It also is integral in the body’s production of needed nitric oxide. Problems maintaining adequate NO levels are associated with high blood pressure, heart disease, and stroke.

Supplemental and enriched folic acid foods should be avoided by those afflicted with MTHFR C677T mutations because the MTHFR mutation has partially destroyed the MTHFR enzyme which is required to process folic acid completely. Those with C677T MTHFR mutations do not process folic acid into 5-MTHF.

How common is MTHFR  Deficiency?

Mild MTHFR deficiency is very common. The table below shows the results of many worldwide studies looking at the C677T mutation. The first number represents the percentage of the population who is a carrier (generally no symptoms). The second number represents the percentage of the population thought to be affected.

Ethnic Group Carrier Rate Affected Rate
Hispanic American 48% 15%
Caucasian American 45% 12%
Japanese 45% 12%
German 37% 6%
Asian 29% 3%
African American 24% 2%
Sub-Saharan African 12% 1%

The A1298C mutation is less well-studied but is also considered quite common. In three studies, the C677T/A1298C mutation pairing was found in 17% of Americans, 15% of Canadians, and 20% of Dutch people. Those who have Italian or Mexican ancestry have a huge rate of MTHFR mutations–upwards of 50% (1 out of 2 people). All in all, estimates reveal; 20% of Americans have symptoms.

Make sure your folate supplements are an L5-MTHF preparation. A simple way to test for the mutation is to check your folate level. If it’s sky high, you’re not using your folate and have a good chance of having the genetic mutation. Also, checking homocysteine levels is a good idea. A high homocysteine level is highly suggestive of an MTHFR deficiency.

The problem with “unused” high folate levels

If folic acid does not turn into 5-MTHF, folic acid levels build up. Elevated folic acid has potential to stimulate pre-existing cancer cells. If your body is not activating folic acid, it could be disrupting other nutrients and processes, including the production of neurotransmitters, detoxification of estrogen, and production of vitamin B12.

This can result in anxiety, fatigue, brain fog, as well as greater risk of cancers, Alzheimer’s disease, heart disease, and diabetes. It can also cause fatigue, irritability, sleep issues, and/or aches and pains—and often there is no apparent cause. Doctors frequently say, “There’s nothing wrong” because standard blood results all fall within “normal” ranges.

Even when a diagnosis is given for fibromyalgia, chronic fatigue, and/or autoimmune disease, it is rarely thought that this relatively common undiagnosed and easily treatable genetic issue could be the underlying cause. Do make sure your folate supplement is methylated. That’s the correct form of folate to use for supplementation.

What form of this Essential B Vitamin should you take?

Vitamin B9, also called folate or folic acid, is one of 8 B vitamins.

the very most important b vitamin is found in these foodsFolic acid is the synthetic form of B9, found in fortified foods and supplements. Folate occurs naturally in foods. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which the body then uses to produce energy.

These B vitamins, or B-complex vitamins, also help the body use protein and fats.

B-complex vitamins are vital for “good skin,” as well as healthy hair and eyes.

They also help the nervous system function properly. All the B vitamins are water-soluble, meaning the body does not store them. Our bodies need folate to make DNA and other genetic material. The body’s cells use folate to divide. If you do not have a methylation issue and you eat enough folate-rich foods you don’t need to supplement. However, if you have been tested, or you think that this article applies to you, you need the 5-MTHF form of folate to bring down an elevated homocysteine and correct detoxification pathways and so on.

What foods provide folate?

full of the essential b vitamin folateFolate is naturally present in many foods, and food companies add folic acid to other foods, including bread, cereal, and pasta.

Green leafy vegetables (or foliage) are among the best sources of folate. Specifically, spinach, turnip greens, and romaine lettuce are top sources of folate.

Other vegetables such as broccoli, asparagus, cauliflower, and beets are high-folate too. You can get what you need with a variety of foods. Fruits, specifically oranges, papayas, and strawberries, are high in folate. Nuts, beans, and peas (such as black-eyed peas, garbanzo beans, navy beans, kidney beans, and pinto beans) are good sources of folate unless you are avoiding lectins due to leaky gut or inflammatory bowel disease. I do not include grains here because I’m phasing them out of the diet plans I recommend (which you can read about in my superfoods article).

This list above is for you if have normal folate metabolism and are trying not to supplement. If you are unsure of your methylation status, please remember, eating these foods will not help your folate status. Having an MTHFR deficiency is as if you are “low folate” which can produce all sorts of medical problems.

Health concerns associated with low folate

Neural tube defects

Taking folic acid regularly before becoming pregnant and during early pregnancy helps prevent neural tube defects in babies. However, half of all pregnancies are unplanned. Therefore, all women and teen girls who could become pregnant should consume 400 mcg of (MTHF) folic acid daily from supplements.


Folate that forms naturally in food may decrease the risk of several forms of cancer. However, folate might have a different effect depending on the dosage and time of ingestion. Reasonable doses of (MTHR) folic acid taken before cancer develops might decrease cancer risk, but high doses taken after cancer begins (especially colorectal cancer) might speed up its progression.

For this reason, take caution when ingesting high doses of folic acid supplements (more than the upper limit of 1,000 mcg), especially for those who have a history of colon polyps (adenomas). More research is needed to understand the roles of dietary folate and folic acid supplements in cancer risk. Folic acid in the diet seems to protect against the development of some forms of cancer, including cervical, stomach, breast and pancreatic cancer.

However, this evidence derives from studies on the population showing people who get enough folate in their diet have lower rates of these cancers. Researchers do not know exactly how folate might help prevent cancer. Some think folic acid keeps DNA healthy and prevents mutations that can lead to cancer.


People with low folate levels might be more likely to suffer from depression. In addition, they might not respond as well to treatment with anti-depressants. Considerably more research is necessary to learn about the role of folate in depression and whether folic acid supplements are useful in combination with standard treatment.

Brain and Nervous System Health

Folate helps support nervous system function. It is crucial for the production of messaging molecules which our nerves use to send signals throughout the body. There has been a lot of recent knowledge acquired about folate’s role in the production of brain chemicals (neurotransmitters) and brain health including memory in general.

In the “BH4 Cycle” (where BH4is an abbreviation for tetrahydrobiopterin), researchers reveal a close connection between the production of multiple neurotransmitters (with particular emphasis on serotonin and dopamine) and availability of folate.

Most dopamine production in our nerve cells begins with the conversion of one amino acid (phenylalanine) into another amino acid (tyrosine). There seems to be a connection between folate availability and this neurotransmitter pathway since BH4 is mandatory for the conversion of phenylalanine into tyrosine.

There are also possible connections between two additional neurotransmitters—glutamic acid and GABA—and folate metabolism. Glutamate is excitatory while GABA is calming; you need the proper balance of these two to fall asleep, as one prime example.

Age-related hearing loss

One study suggests that folic acid supplements help slow the progression of age-related hearing loss in older adults with high homocysteine levels and low folate in their diet.

Age-related macular degeneration (AMD)

One large study shows women taking 2,500 mcg of folic acid along with 500 mg of vitamin B6 and 1,000 mcg of methylcobalamin (vitamin B12) daily reduce their risk of developing AMD. Other studies also added carotenoids such as lutein and zeaxanthin; I firmly believe these nutrients are exceptionally important for ocular health.

Specific Support of Red Blood Cell Production

Folate is one of many nutrients the body needs to produce red blood cells. These cells carry oxygen from the lungs to other parts of the body.

Heart disease and stroke

The key role of folate in cardiovascular health does not stop at the production of red blood cells. In fact, the overall cycle used by our body to regenerate active forms of folate—called the folate cycle—is directly tied to the methylation cycle in cardiovascular health. In cardiovascular disease, this cycle continually interconverts the amino acids methionine and homocysteine. When our methylation cycle breaks down, there is a breakdown in our conversion of (dangerous) homocysteine back into methionine.


If you are taking a folate supplement, it’s best to take methylated supplements no matter what your genetic type. Similarly, if you take the other essential B vitamin, B12, you should always look for methylcobalamin; not cyanocobalamin. Although all of the B’s are important, these are your most significant B’s to take in the above-suggested forms.



  1. I read with great interest your article on MTHFR deficiency, since I have both high folate and high homocysteine levels.

    • Marietta-
      You likely do indeed have a methylation defect and this truly affects your clearance of toxins. Please take a methylated form of folate and B12 with B6 being needed too. Best, Dr.Kim

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