Vitamin B12
A Vital Multitasker

Vitamin B12, alias cyanocobalamin, doesn’t work alone.   It has a couple of friends in the person of vitamin B6 and folate.  They form a triad and we need to be tight with all three. 

B12 is a strange one though.  For starters, it is essential which means that we can only get it from food but the only food that will supply it is animal flesh.  The implications are pretty grim for vegans and vegetarians, a dietary lifestyle that virtually guarantees a vitamin B12 deficiency unless it is supplemented.

It turns out that there are different forms of vitamin B12.  Because B12 is the only vitamin that has an ion of the metal cobalt, “cobalamin” was selected to refer to compounds having vitamin B12 activity.  

The human body can use two forms of B12, Methylcobalamin and 5-deoxyadenosyl cobalamin.    Cyanocobalamin is the form of cobalamin used in most supplements as it is readily converted to 5-deoxyadenosyl and methylcobalamin in the body.


What a B12 deficiency exposes one to is not good.   For starters, how does mental impairments or even Alzheimer’s sound?  

Since it is needed to create myelin, the sheath or insulation that covers neurons, a deficiency translates to an impaired nervous system as in multiple sclerosis, dementia or Alzheimer’s.   It is fairly common for a diagnosis of Alzheimer’s to be nothing more than a B12 deficiency. 

Does increased risk for heart attacks sound better?  High blood levels of homocysteine are common to both cardiovascular and cerebrovascular diseases.  

Research has shown that insufficient amounts of folic acid and vitamin B12 can elevate homocysteine levels, potentially increasing the risk for heart disease and stroke.

This vitamin is also needed for DNA synthesis so it figures that a deficiency presents the potential for damaged cellular DNA and all the hazards that entails; think replication of damaged and mutated DNA as in cancer.    For example, inadequate levels of B12 have been shown to raise the risk for breast and cervical cancer.
Since vitamin B12 is needed to make red blood cells, the least serious deficiency might be anemia, fatigue or cognitive problems due to reduced oxygen levels to the brain.

Maybe you would rather go blind.  Optic neuropathy, deterioration of the optic nerves, is another outcome of vitamin B12 deficiency. Long-term, chronic B12 deficiency is known to result in blindness and this is a one-way street; it is irreversible.
While we’re on the subject of deficiency, here is another complication.   Vitamin B12 is water-soluble so one would think that it would be expelled in urine if we get too much.  

Not so with this guy…it wants to be different from the other water-soluble vitamins so B12 doesn’t exit our bodies in urine; it gets stored in the liver, kidneys and other body organs.  

In fact the body can store about two years worth of B12 which means that a deficiency might not show up for several years.  It all depends on ones diet and the body’s ability to absorb B12; more on absorption later.

Storage in body organs and the resulting time lag is no small matter.  Above we mentioned that a B12 deficiency can cause mental impairments.  The bad news is that after about seven years of B12 deficiency, irreversible brain damage can result.

The sad fact is that so many misdiagnosed health issues are nothing more than a B12 deficiency that a book has been written about it.  After going through this web page, you may want to come back and order the book from Amazon via the image link.

Interaction Deficiency

There are numerous prescription medications, over the counter remedies and substances that work to block absorption of B12 and thus contribute to deficiencies.
Diabetes is fast becoming a worldwide epidemic and the prescription drug Metformin or any of its popular brand names can impair B12 absorption by degrading the metabolism of calcium in the body.   Calcium is a necessary element for the absorption of several vitamins and B12 is one of them.  

Time and dosage come into play for type 2 diabetics; high dosages over extended timeframes increase the risk of a B12 deficiency.

Once upon a time dentists widely used nitrous oxide for anesthesia and it turns out that this rather benign gas tends to destroy B12 reserves in the liver.   Who would have known?
Over the counter remedies for acid reflux or anything that tends to reduce the amount of stomach acid will interfere with our absorption of B12. 

An adequate amount of acid, such as hydrochloric acid in the stomach, is necessary for proper digestion and thus adsorption of B12.  Also worthy of mention is that gastric bypass surgery will also reduce B12 absorption.  
Research has shown that coffee lovers having over four cups of the brew a day are risking a 15% reduction of their vitamin B levels that those that don’t partake. 

Not to worry, other research shows that coffee drinkers are at a lower risk of stroke that those that don’t drink coffee.   Keep the coffee flowing and supplement the B complex.
Metformin was mentioned above as inhibiting vitamin B12 absorption.   It turns out that there is a lot of company in this crowd.  Here is a short list of classes of prescription meds that could interfere either with B12 levels or its absorption.  It is not inclusive of all interfering drugs but it gets the point across.

  • antibiotics
  • statins (cholesterol lowering drugs)
  • birth control pills
  • high blood pressure meds (hypertensives)
  • mood altering drugs (antipsychotics)
  • chemo drugs (anti-cancer treatments)
  • Parkinson’s drugs
  • Getting Technical about Absorption

    As mentioned above, absorption depends on an adequate supply of stomach acid and something called an intrinsic factor from the parietal cells in the stomach.   It’s the intrinsic factor that releases the B12; and the production of acid as well as the intrinsic factor is reduced as we age.
    Well, since we mentioned intrinsic factor, perhaps some explanation is in order.   The short version is that intrinsic factor is a protein, specifically a glycoprotein; a protein with branches of complex sugars attached to it.

    It is produced by the cells lining the stomach, known as parietal cells, along with the hydrochloric acid.  The intrinsic factor’s job is to bind with a B12 molecule and go hand-in-hand through the small intestine and into the large intestine. 

    Since the B12 molecule is very large, it would not be able to be absorbed without help; that’s where the glycoprotein intrinsic factor saves the day.   It gets absorbed first by the cells of the large intestine and since it is bound to the B12 molecule, it pulls the B12 into the cell with it. 

    From there it is easy to be absorbed and used by the body where it is needed.   In reality, the process is much more complex than that, but this is not intended to be a course on absorption.
    The point is that we can supplement with vitamin B12 pills all day but without the intrinsic factor, none of it would ever be absorbed.  Remember how we said antacids and acid reflux meds retard acid production in the stomach?   

    The message is that if we aren’t producing enough stomach acid, then by default we aren’t producing enough intrinsic factor either and we will become B12 deficient.

    This brings up the option of getting vitamin B12 shots to remedy a deficiency.   A B12 shot right into the vein bypasses the whole absorption process and puts the vitamin directly into the blood stream and cuts stomach acid and the intrinsic factor out of the action.
    After reading the above, one might wonder how anyone would ever get enough B12.   As we might suspect, many of us don’t.  According to the famous Framingham Heart Study, 25% of the adults in the U.S. are deficient in B12 and over half have blood levels that are low in B12.  This brings us to the numbers.

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    Testing:  Enough is Enough and
    How to Know

    In checking with our friends at NIH’s Office of Dietary Supplements, we see that the RDI for vitamin B12 increases with age.  

    It begins with .4 mcg at birth to 6 months and rises to 2.4 mcg for teens and adults.  It is slightly higher for pregnant teens or women and breastfeeding mothers, at 2.6 and 2.8 mcg respectively.  

    Recall that an RDI is geared to healthy individuals, not sick or vitamin deficient people.

    The good news is that B12 is non-toxic and there is no such thing as too much.

    In doing a lab screening for vitamin B12 deficiency, picomoles per liter (pmol/L) are the units of measure.   In using pmol/L we are dealing with some very large numbers that represent a very small quantity of a substance.  

    A mole is a quantity measure of a substance and one mole of something means it has 6x1023 molecules or atoms; that’s a 6 followed by 23 zeros. A picomole is one-trillionth of a mole.

    The technicians who figured out how to measure and interpret these things have determined that the following values are relevant for screening for a vitamin B12 deficiency:

  • A B12 concentration less than 150 pmol/L is considered B12 deficient and is serious enough that a qualified medical professional should be consulted to determine the underlying cause and treatment.
  • A B12 concentration between 150 and 200 pmol/L indicates that one’s serum Methylmalonic Acid (MMA) level should be measured to determine whether or not the situation requires more investigation and treatment. MMA is a natural compound found in the body and elevated levels are an indication of B12 deficiency.
  • Supplementation and Fortification

    What could be simpler?  If we think we might be vitamin B12 deficient, all we have to do is eat meat, dairy products or supplement. 

    We already talked about the large size of the B12 molecule and how it won’t be absorbed if we don’t have enough intrinsic factor.  So some smart people started thinking about how to shrink the molecule and/or bypass the whole intrinsic factor thing.   

    So far so good, but how do you shrink a molecule without removing some key components.  A molecule of something has to have just so many atoms of the elements that give it identity.  If we remove an atom here and there, we no longer have that same substance.
    So science took the route of bypassing the stomach and need for intrinsic factor.  It was found that the molecule could be absorbed easily by fine capillaries in the mouth if it was placed under the tongue or between the cheek and gums (we're talking B12 here, not snuff).   

    The fastest, most efficient form of delivery was found to be in the form of spray containing microscopic droplets of vitamin B12.
    This method bypasses the intrinsic factor problem and is much easier, safer and less painful than a vitamin B12 shot.

    We could examine the labels on food packaging and look for cobalamin or B12.  We would probably find that most breakfast cereals are fortified with B12.  

    The problem is that most breakfast cereals are high glycemic and quickly break down into sugar which stimulates insulin production.  Getting a little extra B12 through highly processed cereals in not worth the wear and tear on the pancreas and risking type 2 diabetes.</p>
    Since vitamin B12 supplementation is safe and cheap when compared to the cost of a lab test, it just makes sense to supplement first and see if symptoms recede before getting a test or a B12 shot. 

    Anyway, if a lab test shows a deficiency, the first thing the doctor will suggest is supplementation so why not beat him to the punch and just do it.

    Let’s Not Forget the Ladies

    We already said that B12 deficiencies will raise homocysteine levels.  We know what that does to our cardiovascular system…not good. 

    For women, the news is not good if pregnant.  Homocysteine can also lead to birth defects and increase the risk of complications during pregnancy.
    Neural tube defects are a type of birth defects that affect an infant’s brain and spinal cord.  Spina bifida is a type of neural tube defect that can result in paralysis.

    Neural tube defects start developing in the first four weeks of pregnancy so it is imperative not to wait before checking on B12 levels.
    B12 deficiencies have also been linked to difficulties in becoming pregnant or in infertility.   The last consideration is breast feeding.  If a breastfeeding mother is vitamin B12 deficient, abnormalities could develop in the baby’s brain.

    Considerations In Relying on
    Food for Vitamin B12

    Seafood is a great natural source of B12 but the downside is that most fish and even shell fish are contaminated with heavy metals.  It doesn’t make much sense to garnish your B12 with mercury.  This is especially true if pregnant since mercury extremely harmful to central nervous system development in a fetus or child.
    Beef, chicken and pork are all good sources of B12 if you can find an outlet selling grass fed beef; organic free range chickens or non-factory farm raised hogs.  

    In fact, it is best to avoid factory farmed animal products of any type due to the chance of consuming antibiotics, growth hormones or slaughter house pathogens.  Try your local farmers market.
    Milk and eggs are two great non-meat sources of vitamin B12 but there is a “however” here as well.   Organic is the way to go to avoid the same antibiotic, hormone and pathogen exposures present in most animal factory products.

    Some nutritionists recommend unpasteurized raw milk which is OK if you know that how it was produced, handled and bottled.  Pasteurization of milk started for a reason so it is best to know your source and if you don’t, try to find a Certified Grade-A milk, produced under government supervision and guaranteed clean.  Lotsa luck with that one.

    There are a few plant foods that have B12 but along with the B12 most of them also have a substance called an "analog" that tends to block the absorption of B12.   Forget about relying on plant sources for your B12 requirement; it won’t happen.

    In Summary

    In summary, making sure that we have the right levels of vitamin B12 will greatly improve our quality of life, ward off a myriad of health challenges, give our cognitive abilities a fighting chance and help with a good night’s sleep.

    Supplementing with at least the RDI of B12 is a wise move.

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