The Importance of Vitamin B12 & Potential Deficiencies

by lydia on May 31, 2012

The water-soluble B vitamin “complex” is named as such because, in nature, no B vitamin is found in isolation.  They commonly coexist in the same foods and need each other to perform best.  In fact, taking high doses of an individual B vitamin for too long risks depletion of other B vitamins, all of which are essential to good health.

The B vitamins function as coenzymes to catalyze a multitude of biochemical reactions within the body.  They are essential for carbohydrate, protein and fat metabolism and energy production.  They support the adrenals and nervous system, mental health and stress reduction, and help maintain healthy skin, hair and eyes.

Today’s focus is on vitamin B12 – a deficiency that is far more prevalent than is diagnosed.

Vitamin B12 is crucial for the health of the nervous system.  The myelin sheath – the insulating layer that wraps around nerves and allows for impulses to transmit quickly and efficiently – will not form properly in the presence of a B12 deficiency, thus exposing nerves to damage.1  Much of the so-called symptoms of “normal aging” – Alzheimer’s, dementia, memory loss, etc. – are also symptoms of vitamin B12 deficiency.

Vitamin B12 helps iron function and is important for the synthesis of DNA and RNA, the production of choline (another B vitamin) and methionine (an amino acid).2  In addition, vitamin B12, along with iron, folic acid, copper, protein, and vitamins C and B6, is needed for the proper formation of red blood cells; deficiency leads to oversized and poorly shaped cells (part of the condition known as pernicious anemia).2

Another destructive consequence of vitamin B12 deficiency is the appearance of homocysteine in our blood.  Dr. Cordain notes, “Without sufficient dietary sources of vitamin B12, a chemical reaction within our bodies is impaired and causes blood concentrations of homocysteine to rise.”  He continues, “Homocysteine is a toxin for almost every cell in our bodies.  It increases the risk for birth defects, infertility, dementia, psychological illness, stroke, heart attacks, blood vessel disease, blood clots, osteoporosis, and overall death rates.” 4

Perhaps most unsettling is the fact that pregnant women who are deficient in vitamin B12 can pass this deficiency onto their unborn child, who are then likely to suffer from congenital malformation, failure to thrive, apathy, mental retardation, and developmental problems.  B12 deficiency has been known to cause spontaneous abortions, weak labor, premature and low-birth-weight deliveries, birth defects, and preeclampsia (maternal high blood pressure and damage to the liver, kidneys, and blood vessels).4

Vegetarians, in particular, are at risk for low levels of vitamin B12.

Vitamin B12 is unique in that it is found in animal protein foods exclusively.  As noted by Dr. Chris Kresser in his research, “plant foods said to contain B12 actually contain B12 analogs (called cobamides) that block intake of and increase the need for true B12.” 3  Furthermore, in his book The Paleo Answer, Dr. Loren Cordain points out, “If you decide to become vegan, by default you will become vitamin B12 deficient unless you supplement your diet with this essential vitamin.” 4  It comes as no surprise, then, that a 2003 study conducted by Dr. Hermann of ninety-five vegetarians concluded that 77% of lacto/ovo vegetarians and an astounding 92% of vegans were deficient in B12.  This study is representative of nearly all studies reporting vitamin B12 levels in vegetarians.4

So what about the rest of us who are eating animal products?  Certainly vitamin B12 deficiency would be a non-issue.  Not quite.  According to the findings from the Framingham Offspring Study, nearly two-fifths of the American population suffers from a “low normal” range of plasma B12 levels. 1  Why is this the case?  The answer lies in the body’s ability to absorb and utilize the vitamin.

Vitamin B12 is always bound to protein in a food. Hydrochloric acid production in the stomach is required to “release” B12 from its protein.  B12 must then combine with a mucoprotein enzyme, called intrinsic factor (IF), in order to be absorbed into the bloodstream. 5  Because much of the U.S. population suffers from low stomach acid production (especially if there is a history of antacid or acid-suppressing drug use, but also the result of other issues) eating sufficient amounts of animal protein won’t necessarily save you from a B12 deficiency.  This is why proper digestion is so fundamental to overall health, as it ensures the adequate breakdown, absorption and assimilation of nutrients.  Taking the time to “rest and digest” before a meal so that the brain recognizes food is coming, eating slowly and chewing thoroughly, avoiding highly refined carbohydrates and sugar, eliminating potential stressors (such as dairy, grains or legumes) which may irritate the gut lining and cause inflammation, are all critical components of proper digestion.

It’s important to recognize the signs of insufficient levels of vitamin B12.  

If a slight B12 deficiency exists, symptoms may be nonexistent to mild.  As it worsens, symptoms may include the following:
•    Soreness or weakness of limbs
•    Fatigue, light-headedness
•    Rapid heartbeat and breathing
•    Pale skin
•    Red or sensitive tongue (known as “strawberry tongue”)
•    Easy bruising or bleeding, including bleeding gums
•    Upset stomach and weight loss
•    Diarrhea or constipation2,6

If not corrected, a more severe B12 deficiency may lead to nerve cell damage, which may result in the following symptoms:     

•    Tingling or numbness of fingers and toes
•    Difficulty walking or speaking
•    Diminished reflex response
•    Mood changes or depression
•    Memory loss, mental slowness, dementia, or disorientation2,6

If you believe you may be vitamin B12 deficient, it is important to get tested.  The most common and widely used confirmatory tests for identifying a B12 deficiency are homocysteine (Hcy) and methylmalonic acid (MMA) tests.  The good news is that these tests are quite affordable, even if you aren’t covered by insurance.  If the root of the deficiency is not obvious, you may also consider additional tests to determine the cause.  Antibodies to intrinsic factor (IF and gastrin or pentagastrin I levels are often used to diagnose the autoimmune disease, pernicious anemia.7

Some excellent sources of vitamin B12 are:
•    Shellfish (calms, oysters, mussels)
•    Organ meats (liver, heart, kidneys)
•    Fish (especially the oily ones, like trout, herring, and mackerel)
•    Crab, lobsters, scallops and shrimp
•    Meat (beef, lamb, etc.)
•    Cheeses and cultured yogurt

If you are a vegetarian or vegan, supplementing with vitamin B12 is essential.  Because vegetarians usually have a high folic acid intake, and because folic acid and B12 work similarly in the body, a deficiency may be masked for some time before more pronounced symptoms occur.2


Today’s post is brought to you by my friend &  fellow NTA colleague Ann McHugh, NTP. Ann blogs at The Coconut Frontier. Find her on Facebook as well.



Cited Resources:
    •    Judy McBride (January 2012). B12 Deficiency May Be More Widespread Than Thought.  Agricultural Research.  Retrieved from
    •    Dr. Elson M. Haas (2006) Staying Healthy with Nutrition.  Berkeley, California: Celestial Arts.  
    •    Chris Kresser (May 2011).  B12 deficiency: A Silent Epidemic with Serious Consequences.  Retrieved from:
    •    Dr. Loren Cordain (2012).  The Paleo Answer.  Hoboken, New Jersey: John Wiley & Sons, Inc.
    •    (October 2011).  Vitamin B12.  The Mayo Clinic.  Retrieved from:
    •    (April 2012).  Vitamin B12 Deficiency.  WebMD. Retrieved from:
    •    (June 2009).  Vitamin B12 Deficiency: Detection and Diagnosis.  Centers for Disease Control and Prevention.  Retrieved from:

( feature photo credit)





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{ 7 comments… read them below or add one }

Debra E June 17, 2014 at 1:30 pm

My Dr. told me yesterday that my lab results showed a high homocysteine of 15.6! So I got on this site to find out if there was any information about supplementing for B12 (which she recommended) and found this excellent article that explains a little bit more about it than she did! So do you have a recommendation or good resource about supplementing B12?


lydia June 17, 2014 at 2:45 pm

Eat more liver 😉

Source Naturals has a nice sublingual B12.


Debra E June 17, 2014 at 1:46 pm

Oh, and any recommendations for supplements for Folate as well?


lydia June 17, 2014 at 2:20 pm

Eat liver, cooked greens – but really liver is exceptional. 1/4 lb weekly is a good amount


Debra E June 17, 2014 at 4:34 pm

Yeah, right. Since I’ve mastered enemas now I guess liver is the next thing to tackle? I have some beef liver cubes to try to figure what to do with and I actually have some chicken livers in the freezer to try your pate recipe, except I haven’t introduced dairy back into my diet yet. Suggestions for a GAPS/AIP person? I’m keeping it pretty simple for me with grilled hamburgers and soups/stews. Other than trying to put the liver cubes into the meat for our cheese dip previously, I haven’t worked with liver at all!

And if I do get 1/4lb. per week of liver into me, do you think I should still do a supplement folate as my Dr. recommends or in your opinion would I get enough folate from the liver w/o extra supplementation?


lydia June 18, 2014 at 5:46 am

You can use duck fat for the pate. Are you able to tolerate ghee? I would use ghee if that is the case. I use beef liver cubes in any ground beef dish I make.

I think the 1/4 lb liver (beef/lamb are higher in folate) a week is probably going to be enough. If you don’t think you can get that in perhaps having a supplement on hand would be a good back up plan.


Debra E June 18, 2014 at 10:50 am

I haven’t tried ghee, but the duck fat is an excellent idea as well! I’ve never tried it but I’m willing! I suppose that would be an interesting experiment to not take the supplement Vitamin D, B12, or folate and just get my liver in and see how my labs are in a couple months when I see the Dr. again.

To make sure I understand…beef/lamb liver would be higher in the folate and chicken liver would be higher in the vitamin K? And if I don’t think I’ll be getting the 1/4lb per week do you have a good source for dessicated liver?


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