Six Commonly Missed Diagnoses: B12 Deficiency

Posted 05/14/2012

You’re pretty sure you know your body and you tell your doctor you’re just not feeling right. You’re tired, maybe a little depressed, a bit achy. Maybe your digestion is “off.” The list of foods you can’t seem to enjoy is definitely longer. Your doctor’s empathic, not at all dismissive of your symptoms, but after a physical exam and some apparently appropriate tests she can’t find anything really wrong.

On the surface, this is reassuring. After all, the main reason we do go to doctors is to ascertain that nothing serious is going on. Still, could she be overlooking something?

After decades of treating patients with longstanding but undiagnosed chronic symptoms, here’s the first of six overlooked diagnoses I see most frequently in our patients at WholeHealth Chicago.

Low Levels of Vitamin B-12
One of the eight B vitamins, B-12 is involved in the metabolism of every cell in your body. Years ago B-12 was called “maturation factor” because cells need B-12 to mature from being young and ineffectual whippersnappers to fully functioning and mature.

B-12 deficiencies affect three major systems in your body: your blood, nervous system, and, less often, gastrointestinal tract. These three are targets because their cells either have a high turnover rate (blood and intestinal lining) or need a lot of B-12 to function smoothly (nervous system). The symptoms of low B-12 levels are related to each of these areas.

  • Low B-12’s effect on your blood is a specific type of anemia called megaloblastic anemia (as distinct from the more common iron deficiency anemia). A megaloblast is an immature, undeveloped red blood cell, large and bulky (megalo=large, blast=immature form). Remember, B-12 is needed for this cell to mature, so with insufficient B-12 megaloblasts accumulate in your blood. Symptoms are the same as for anemia from any cause, including fatigue, breathlessness, and lightheadedness. Your skin becomes a pale yellow, most likely because the red cells that do make it to maturity are very fragile and easily broken, releasing their yellow bilirubin pigment.
  • In your nervous system, B-12 deficiency causes symptoms affecting your nerves (numbness, tingling, tremors, balance problems) and your mind (depression, brain fog, mood swings, and, in rare cases, hallucinations and psychosis).
  • In your gastrointestinal tract, you might experience digestive symptoms and weight loss because you’re not absorbing food efficiently.

The irony is that with all these there’s usually just one predominant symptom, and making a connection to low B-12 can easily be delayed until other symptoms start to appear. For example, if your only symptom is tingling in your hands, you might undergo all sorts of diagnostic tests before your doctor thinks “Maybe we should check her B-12 level.”

What causes B-12 deficiency?
The list of causes is lengthy, but by far the most frequent culprit is a dietary one. Vegetarians who aren’t paying attention to the B-12 in their food choices will have downward-drifting B-12 levels, and virtually all vegans not taking Vitamin B-12 supplements ultimately develop deficiencies. Even the various vegan organizations acknowledge it’s not possible to get adequate B-12 while following a strictly vegan diet, and that’s because the richest sources are animal products.

Other causes of B-12 deficiency include pernicious anemia, an uncommon (and spookily named) autoimmune disease that destroys parietal stomach cells. These cells produce a substance called intrinsic factor, necessary for B-12 absorption. Also, since you need stomach acid to absorb B-12, long-term use of acid-suppressing proton pump inhibitors (Nexium, etc.) can lead to B-12 deficiency, as can chronic intestinal conditions like Crohn’s disease, celiac disease, and intestinal parasites.

The missed diagnosis
The main danger of missing this diagnosis is that (while quite rare) the damage to your nerves and even brain can be permanent. Other serious consequences: your anemia can get so severe it causes heart failure and collapse. Or you could be misdiagnosed with a major depressive disorder or even psychosis and take unneeded psychiatric medications for months (or years) before someone notices you look yellow-ish and you’re finally diagnosed with megaloblastic anemia.

There are four reasons why this diagnosis is missed:

  1. Although it’s not an expensive test, B-12 isn’t measured during routine blood tests. Doctors generally don’t order a B-12 evaluation if there’s no evidence of anemia (which would be picked up on a routine blood test). However, the fatigue and nervous system and gastrointestinal symptoms can precede anemia by months.
  2. Doctors rarely ask (and patients rarely volunteer) information about their eating habits. In medical school, we’re taught that the US diet is “plenty good enough to prevent any vitamin deficiencies.” To which I now respond, “Ha!” I agree most of us eat plenty of food (obesity levels are still on the rise), but it’s often food whose nutritional value has been castrated. Also, all vegetarians and vegans should be regularly tested for possible B-12 deficiency, but if your doc doesn’t know your eating habits you won’t be tested.
  3. Like many blood tests, there’s considerable disagreement about normal levels of B-12. Most labs test B-12 levels between 200 pg/ml (picograms per milliliter) and 800 pg/ml. Someone at 250 pg/ml would be classified as normal, but symptoms can start appearing at 350 pg/ml. In Japan, normal B-12 was recently raised to 500 pg/ml and higher. We’ll see this type of erroneous overreliance on “normals” in other frequently missed diagnoses, like hypothyroidism, vitamin D deficiency, gluten intolerance, adrenal fatigue.
  4. Taking the B vitamin folic acid (folate) or eating a lot of folate-containing foods without adding B-12 can actually mask the symptoms of a developing B-12 deficiency. Although folate will keep your blood count normal even if your B-12 is falling, the folate will not protect your brain and nervous system. You’ll have no evidence of megaloblastic anemia (because of the folate), but your symptoms of numbness, tingling, balance problems, and emotional issues will continue unchecked. By eating so many folate-containing green vegetables, beans, and lentils, vegetarians and vegans inadvertently mask their own slowly developing B-12 deficiency.

Treatment is easy
It’s virtually impossible to take too much B-12 as any excess of this water-soluble vitamin is eliminated via urine. Nutritional guru Alan Gaby, MD, has commented that the only way too much B-12 will kill you is if you fill your bathtub with it and drown.

Foods high in B-12 are animal products: meat, poultry, seafood, dairy, and eggs, with eggs having the least. Because all animals store B-12 in their livers, eating liver is an excellent (though not particularly popular) treatment for B-12 deficiency. Your grandmother or great-grandmother likely remembers a time when her doctor told someone in the family to eat more liver.

And since people with low B-12 are likely to also have gastrointestinal symptoms that interfere with B-12 absorption, the best way to quickly increase (and maintain) B-12 levels are with B-12 injections, chewable tablets, or the recently released nasal sprays and skin patches.

In my own practice, a deficient patient receives a series of four B-12 injections (or four B-12 containing Meyer’s Cocktails) and also starts (and maintains herself on) a daily B-12 chewable tablet. Usually within a month her levels are back to normal.

There’s more to come in the Commonly Missed Diagnoses series. Next week: overlooked diagnosis #2, vitamin D deficiency

Be well,

David Edelberg, MD

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404 comments on “Six Commonly Missed Diagnoses: B12 Deficiency
  1. Surgery doctors need to understand more these days – I did work in a surgery so I am familiar with the routine but when I changed surgeries to become a driving instructor I was disappointed with a couple of them!!

  2. Excellent information. Just posted this on an ALS forum.

  3. wolf max says:

    thanks for that. i’m getting gradually more cold/numb in hands/feet and fatigued, etc etc. and full of joint pain/injuries, so luckily came to realize i have morton’s foot which comes from a p5p deficiency, so to prove if quackery or legit, i chose to test b2 b6 b9 b12 and homocysteine and found off charts high homocysteine, off charts low b2 which were expected and apparently indicate inability to convert b6 to p5p thus no p5p to convert homocysteine etc. and likely others deficiencies inherent. anyway, i’m looking for a similar article for b2 deficiency and vitamin d. thanx.

  4. Debbie Johnson says:

    Wow! Very helpful information. Excellent explanation that is easily understood.

  5. Adeline Mikka says:

    Want to know more. I have been diagnosed with a brain cloud but all subsequent tests have “normal” results. What can this be? I am female 67 years old.

  6. cliffmaurer says:

    This can be due to a variety of causes. Do you have access to a functional or integrative medicine physician? If you’re in the Chicago area, we’re happy to help.
    -Dr M

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