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Vitamin B12 Basics

Vitamins are remarkable “helper” molecules that play essential chemical roles in every one of our cells. There are two families of vitamins: vitamins that dissolve in fat (such as vitamins A, D, E, and K) and water-soluble vitamins (vitamins B1, B2, B3, B5, B6, B12, B13, and B15).

Vitamin B12, also known as cobalamin, is a beautiful, complex molecule with a single atom of cobalt at its center. In your body’s cells, vitamin B12 plays a vital role in the synthesis of DNA and, thus, is essential for the health of your blood and bone marrow, as well as maintenance of your nervous system, including your brain, spinal cord, and peripheral nerves.

Chronic, severe deficiency of vitamin B12 can lead to anemia, dementia, paralysis, and death. As a result, maintaining adequate levels of vitamin B12 in your tissues is vital to your well being.

Primary Sources of Vitamin B12

Since vitamin B12 is found in the muscles of animals – and, thus, consumed in meat – it is commonly thought of as available only through consumption of animal products. It is important to understand, however, that animals do NOT make vitamin B12. Instead, vitamin B12 is exclusively made by microorganisms living in soil and water.

Cows, deer, and other free-living, grazing animals have vitamin B12 in their muscles and flesh because they eat grass with B12-producing organisms in soil particles that cling to plant roots. This MICROBIAL-produced B12 is swallowed, absorbed, and deposited in the muscles of animals, but cows, deer, antelope, etc. do not make it. It is that BACTERIA-made cobalamin in an animal’s flesh that omnivorous people consume when they eat meat “to get their B12.”

In earlier times, humans acquired vitamin B12 in the same way. Our ancestors spent most of their daytime hours foraging for foods and most of their calories came from roots and tubers pulled up from the ground. Those plant parts were eaten without first being washed in (modern-day) chlorinated drinking water. As a result, humans ingested bacterial B12 from the surface of root vegetables, just as the grazing animals did (and do).

When humans were thirsty, they would drink their fill from a stream and, in so doing, swallowed more B12-producing organisms in the stream water. Later, when wells were dug, vitamin B12 was present in almost every bucket of well water.

Thus, until the beginning of the 20th century, humans (vegan or not) lived more earth-connected lives, ate harvested plants and drank from streams, rivers, and wells. As a result, there was ample B12 flowing through human bodies from the same, natural sources as swallowed and ingested by grazing animals, which means even vegans could expect to handily meet B12 needs without consuming animal flesh or dairy products.

Now, however, traditional sources of B12 have been virtually obliterated by our modern, sanitized lifestyle. Root vegetables are now scrubbed and washed with chlorinated water, virtually eliminating every trace of natural B12 in the process.

These days, few of us drink water from streams or wells and virtually all of our drinking water is chlorinated, which kills B12-producing organisms. Note: Although chlorination of water has eliminated a traditional source of B12, it also prevents water-borne diseases such as cholera, dysentery, and typhoid fever, which is of great benefit.

As a consequence of the absence of traditional sources of B12, modern day vegans must rely on vitamin B12 supplements to meet their B12 needs.

It is important to understand this requirement is an artifact of modern sanitation and is NOT proof that humans need to eat animal flesh which is not, as stated above, the true and primary source of B12.

The need to ensure a reliable B12 source must be taken seriously. Chronic, severe deficiency of vitamin B12 will lead to anemia, dementia, paralysis, and death. As a result, maintaining adequate levels of vitamin B12 in your tissues is vital to your well being.

Chronic, severe deficiency of vitamin B12 can lead to anemia, dementia, paralysis, and death. As a result, maintaining adequate levels of vitamin B12 in your tissues is vital to your well being.

Blood Tests


When your blood is tested, you want it tested for: (a) Vitamin B12, (b) Homocysteine, and (c) Serum Folate.

Although the lower limit of “normal” Vitamin B12 value is set at 200 ng./L, many people suffer ill effects at that low level, such as fatigue, anemia, sore tongues, and nerve damage. I advise my patients to keep their B12 level well over 600 ng/L.

If there is not enough active vitamin B12 in your tissues – or not enough folate from eating dark green vegetables – then a molecule called homocysteine can build up in your bloodstream. This is NOT good because homocysteine can damage your artery walls and pave the way to plaque formation, heart attack, and stroke!

As a result, if you have a blood test, your doctor should order the homocysteine level, along with the B12 level and serum folate, since the homocysteine value will indicate whether your body’s B12 and folate supplies are adequate.

You want your homocysteine levels well below 12 micromols/L. – and, ample stores of active B12 and folate are required to create this. If your homocysteine levels are above 12 micro mols/L, and your B12 level is below 600 ng/L, double your intake of methylcobalamin for 3 months and recheck the levels again to verify it is getting absorbed.

If your folate level is low, eat more dark green leafy vegetables, including, but not limited to, collard greens, kale, spinach, swiss chard, and turnip greens – and, repeat the test in 3 months.


How Often to Test?


It is wise to have your B12, folate, and homocysteine levels measured 90 days after beginning a supplement program to see if you need to take more or less; then, measure B12 and homocysteine, along with a complete blood count, once yearly for a few years, to verify that your diet and supplement program are meeting your needs.

If your diet is rich in green vegetables and your serum folate is high on the first test, there is no need to measure it again.

You can learn much more about blood levels in my 67-minute On Demand Video and DVD, “Understanding Your Blood Test Results.”


Today’s Vitamin B12 Sources


Fortunately, B12 supplements are produced by microbes in clean, temperature-controlled vessels, are inexpensive and widely available. They’re available in natural food stores and pharmacies in several forms, including as liquid drops and sublingual “microdots” that dissolve under the tongue. (See recommendations below.)

Vitamin B12 is also added to many food products, including, but not limited to, some brands of rice milk, soy milk, nutritional yeast, and veggie burgers. Look for it on the labels of the products you buy.

Since many people do not consume these products, it is wise for people with a plant-based diet to ensure consumption of a reliable source of this crucial micronutrient.


Type, Dose, and Frequency

I advise vitamin B12 supplementation once or twice a week.

Vitamin B12 is sold without prescription in three different preparations: cyanocobalamin, hydroxycobalamin, and methylcobalamin.

Cyanocobalamin is generally the most inexpensive, shelf stable, and, thus, most commonly consumed form. However, many health professionals are not comfortable with this form of B12, because it releases a tiny amount of a toxic molecule, cyanide, as it is metabolized.

Both the cyanocobalamin and hydroxycobalamin forms of B12 require activation by the MTHFR enzymes in our cells to transform them into the active form of B12, methylcobalamin. This chemical step is difficult for some people (10% – 15% of population) who have the homozygous MTHFR mutation. (See “MTHFR Enzyme” below.)

Since methylcobalamin is the active form of B12, and is readily available for cells to use, many physicians, myself included, prefer the methylcobalamin form of vitamin B12 supplement for everyone.

Since vitamin B12 is stored in the liver and muscles, methylcobalamin, 1000 mcg – 2,500 mcg., twice weekly should cover almost everyone’s B12 needs.

I favor B12 supplements in the form of liquid drops or sublingual “microdots” that melt under your tongue because they allow contact of the B12 with a protein in saliva (salivary intrinsic factor) that promotes better absorption into your bloodstream. Here are examples of such products:

Vitamin B12 (Methylcobalamin) Liquid Drops:

Vitamin B12 (Methylcobalamin) Sublingual “Microdots”:

Although vitamin B12 does not occur naturally in nutritional yeast, some brands of nutritional yeast have B12 added by the manufacturer and that can be a convenient and tasty B12 source! Before relying on it as one of the B12 sources in your diet, however, be sure to check the label to confirm whether the brand of nutritional yeast you’re buying is B12-fortified.


Some people feel better after receiving injections of B12 into their muscle. This should NOT be done more than once monthly. It has been shown that consistently taking the oral B12 supplements described above will produce the same blood levels as the injections.


Methylcobalamin vs Cyanocobalamin


Since methylcobalamin is the active form of B12 and is readily available for cells to use, many physicians, myself included, prefer the methylcobalamin form of vitamin B12 supplement for everyone.

Two authors (R. Pawlak; M. Greger) recently asserted that the methyl group on methylcobalamin is removed before methylcobalamin enters the cell and the cobalamin is re-methylated by folate within the cell, thereby making the use of the methylated form unnecessary.

This may be valid, but during my years in clinical practice, I have had several patients with persistent elevated homocysteine levels despite taking large doses of cyanocobalamin. When they switched to methylcobalamin, their homocysteine levels returned to normal levels.

Since cyanocobalamin is less expensive, and if a person does not mind a tiny amount of cyanide in each dose, I would have no objection to that preparation being used long term.

However, if homocysteine levels remain elevated, despite apparently adequate intake of cyanocobalamin, then I would recommend a trial of methylocobalamin at 1000 mcg per day for at least 60 days before re-measuring the level of homocysteine. If levels stay elevated despite treatment with methylcobalamin, a preparation such as Homocystex, which contains folate in the methylated form and other vitamins, may be indicated.


MTHFR Enzyme


If homocysteine levels remain higher than 12 micromols/L, despite B12 levels well over 600 ng./L and folate levels over 5 ng./ml, you may have a deficiency of the MTHFR enzyme that puts B12 and folate into their active, methylated states so they are unable to reduce homocysteine levels.

10% to 15% of Caucasian North Americans have this relative deficiency of the MTHFR enzyme. Healthcare practitioners can test for that gene mutation.

If you have two copies (are homozygous) for that mutation, you may need to take a preparation that has both B12 and folate in their active, already-methylated forms, namely methylcobalamin and methylfolate. Such products include Homocystex or Methyl Guard, available online and in health food stores.

Examples: Homocystex (HomocysteX from Seeking Health) – Methyl Guard (Methyl-Guard Plus from Thorne Research)


In Sum


By paying attention to, and ensuring adequate levels of vitamin B12 and folate following the guidelines above, you can help promote and preserve optimal function of your brain, spinal cord, and bloodstream.

To your good health and happiness,

Dr. Michael Klaper

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