B12 Deficiency – A Common Issue

Article adapted from my bi-monthly newsletter

Molecular structure of vitamin B12

B12 deficiency is important to avoid as humans cannot naturally make the essential nutrient and it is necessary for proper blood and nerve function.  B12 can be found in calf’s liver, sardines, shrimp, scallops and other animal meats.  It can also be obtained from brewer’s yest (a non-animal source).  It takes years of insufficient dietary intake to develop a B12 deficiency and is very common in vegetarians after years of dietary restriction.

 How is B12 extracted from food?

There are several steps involved in extracting B12 from our food.  We first need an acidic environment in the stomach.  Next, we need something called intrinsic factor, which is produced by a specific cell type in the stomach called parietal cells.  The pancreas contributes a protein that must attach to the B12 complex in order to allow a very specific small segment of the small intestine known as the ileum to absorb B12.  Any disorder or condition that interferes with any portion of this complex pathway can promote B12 deficiency.

What is B12 used for?

B12 is necessary for the formation of blood and healthy functioning of the brain and nervous system.  B12 deficiency can be associated with many various systems. Fatigue and depression are very common complaints in B12 deficiency.  Tongue pain and loss of papillae is one physical finding of deficiency (called glossitis).  I have noted patients report muscle cramps when low B12 is found.  Generalized small nerve damage called peripheral neuropathy can develop from low B12.  Balance problems known a ataxia can be seen in B12 deficiency.  Other neurologic symptoms if the problem goes on long or is severe can include Frank Psychosis (going nuts temporarily), delirium (altered mental status/sudden confusion), and even dementia (more long term confusion).  Besides the central nervous system a much more common presentation of B12 deficiency is anemia (low blood hemoglobin) and even fragile red cells which can break up in the circulatory system. When cells break up in our circulation this is called hemolysis. Blood specialist known as hematologists often diagnose B12 deficiency when patients are referred for a diagnosis of anemia.

Do any of you remember the Dracula movies?  I recall the doctor character speaking of the dreaded “pernicious anemia”. Pernicious means highly injurious/destructive and so in the movies that seems appropriate. As opposed to blood sucking vampires from the Dracula movies, medically pernicious anemia is attributed to B12 deficiency that is acquired due to a specific cause. The cause is antibodies against a particular enzyme found in specific stomach cells known as parietal cells. If a person has antibodies against this enzyme system then the enzyme doesn’t function and this results in B12 not getting absorbed from the diet and into the body. Up until recently this form of B12 deficiency required injections (and sometimes it still does) because even if a tablet of B12 is given the patient may still not absorb the product. With today’s liquid products and sublingual products often this form of supplementation can overcome this part of normal absorption and work.  The way to know this is simply to follow the patients B12 level after several weeks of supplementation and from time to time.

 How do I know if I’m deficient?

A simple blood test can detect B12 deficiency.  True B12 deficiency is when a serum level under 200 picograms per milliliter is measured. Relative deficiency is noted when a level between 200-400 pg/ml is measured. Most patients with relative deficiency have no significant complaints.  There are other lab tests that can be run to get further clues as to whether the low normal lab result is already interfering with B12 function/metabolism but I rarely order these tests. I find a moderately high incidence of relative deficiency in my practice, perhaps partly due to the average age of my patients. When this is noted, I recommend patients supplement and do so indefinitely in order to avoid true deficiency.  While people on average use only 6 micrograms of B12 daily, typically supplements come in 1000 to 5000 micrograms. After the storage system is fully restored we urinate any excess B12 that might be taken in. I have found liquid B12 to work the best (other than injections) but many patient do well with simple capsules. Sublingual preparations also work well. This vitamin is readily found over the counter. We do have various options available in the office using the Pure Encapsulations vitamin line. B12 is usually included in multivitams as well. As my prior article indicated, this doesn’t necessarily mean the vitamins are well absorbed. Since the potential problems of deficiency can involve memory and nerves and since sometimes replacement may not correct damage already experienced, I recommend identified patients remain on supplementation indefinitely.  I monitor levels at least annually once I have proven their supplement is working

As we age, we often develop less than ideal digestive function as well as reduced acid production in the stomach and this can promote B12 deficiency. Commonly prescribed medications known as proton pump inhibitors shut down acid production in the stomach. These medications are used to treat acid reflux, heartburn, ulcers and gastritis. Now we can buy these products over the counter; examples being Prilosec, Prevacid and Zegerid. Other acid suppressors include Pepcid AC and Zantac and these also are readily available over the counter as well.  Metformin, which is the main medication used in Type 2 diabetes, has also been associated with B12 deficiency.

Dr. Raymond Kordonowy, MD

Internal Medicine of Southwest Florida

2 thoughts on “B12 Deficiency – A Common Issue”

  1. Dear Dr. Kordonowy, I came across your Blog and this post and had a question. I had my B12 levels checked because I am always tired and my level is 2000. My internist in IL said it’s fine. But I feel like I have the symptoms of LOW B12. Could your levels be high and somehow be deficient somehow? Thank you.

    1. It would be highly unlikely that you could have high levels in your serum and have clinical deficiency. I am not a lab pathologist but I am unaware of any compound that would commonly interfere with the lab test/assay to give a falsely high result. Your doctor could order a serum methylmalonic acid level as well as a homocysteine level and if these are normal you have effectively ruled out both B12 and folate deficiency. Folic acid works in conjunction with B12 and so I suppose it could be plausible if your folic acid level was low you could delay/interfere with B12 processing and promote a high level in your serum. You should be able to eliminate excessive amounts of B12 but I would still advise lowering your supplementation of your levels are measureably high. Too much of a good thing can be harmful as well (Plato had this right,, all things in moderation).

      Obviously fatigue as a single complaint carries a very large differential diagnosis which includes not only B12 deficiency but other causes of anemia (but your hemoglobin would be obviously low on testing), numerous systemic illnesses, sleep disorders, work burn-out and even depression.

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