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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

Posted in Blog, Knowledge Base, S Tagged with: ,
359 comments on “Six Commonly Missed Diagnoses: B12 Deficiency
  1. Kristin D says:

    I stumbled across this thread while searching my symptoms. I have had many low B12 symptoms over the last few months (although I didn’t know that’s what they were) but they have gotten bad in the last couple weeks. I am exhausted – being out of bed for more than an hour or two at a time wears me out. My head feels heavy and just weird (I described it to my doctor as being dizzy but it’s not really dizziness – more off balance), my eyes are spaced out and tired (but I can see fine), I am having brain fog, and my hands and feet go to sleep easily. I had an MRI that I am still waiting on the results of and the bloodwork my doctor did came back normal except he said my B12 level of 382 is low and told me to supplement with 1000 mcg daily. I should also mention that I have a 3 month old baby that I am exclusively breastfeeding. I bought 2500 mcg sublingual methylcobalamin that I have been using twice a day for the last few days. My doctor wants me to follow up with a neurologist as he says a b12 level of 382 wouldn’t be causing the symptoms I’m having. In your experience, can a level like mine be causing these symptoms? After doing some research, it appears that many doctors think the minimum normal levels in the United States for b12 are set too low. I am a busy mom of 3 and don’t have time to be down so much of the time! I am going to call my doctor in the morning and beg for a b12 shot. Would a shot help me immediately? Any insight you can offer will be much appreciated.

  2. cliffmaurer says:

    Hi Kristin –

    Your B12 levels can, in my opinion, cause symptoms like yours, but of course you and your doctor should rule out other causes (the MRI your had and your blood work should be a good starting point for this). B12 levels can take weeks, even months to increase. Injections of B12 can help, but rarely are results immediate. If you’re in the Chicago area, we’d be happy to help if you feel that you’re not getting results.

    Best of luck to you!
    Dr M

  3. Jean Elizabeth Gittins says:

    I cannot tolerate injections- if there is an alternative – which in the event of B12 deficiency I choose B12 Oral Spray – contains Methylcobalamin which is highly recommended. Doctors are not aware of these – you need to purchase the sprays – don’t expect to get them on script!

  4. Jen says:

    Hello, I’ve been following this thread for a while as a lot of my symptoms match with a B12 deficiency. Since May I have had tingling, pins and needles, some numbness and increased floaters in my vision as well as generally tired eyes but I can see ok. My B12 was at 204 but my doctor doesn’t think that is low, really, just a little less than ideal and I m waiting for an MRI to check what’s happening so I am hoping that will be ok. I have been taking 1000mcg a day of B12 for a month now, and wondered how long it normally takes to see a difference in Neurological symptoms…? Also, I have actually stopped taking it for a few days as the symptoms appeared to worsen – I had quite a lot of facial tingling, particularly in my hair line and more burning in my foot than normal. Could these be side-effects of taking a B12 supplement? I have stopped taking them to see if it improves and it does seem to have done. Thank you for your advice and thank you for this blog, it’s very useful indeed.

    Kind regards

  5. Teresa says:

    Hi Jen,

    I had similar symptoms and it took well over a year for the symptoms to go away. I have a MTHFR genetic mutation, so I was taking methylcobalamin 5000 mcg daily, along with methyl folate. Both should be taken together.

  6. Saanjh says:

    This post is very correct. Doctor misdiagnosed my B12 deficiency as depression & he prescribed me antidepressants & anxiolytic. Another neurologist prescribed me vit. 12 & i was completely fine without antidepressants.

  7. Gillian says:

    Just stumbled across this, I have vitb12 deficiency and I am meant to get injections every 12 weeks but my symptoms of pains in my hands feet come back at around 8weeks, had to practically beg my gp to give me injection early she compromised at 10weeks. Is it common to need injections sooner? Is it harmful to get them sooner? It helped so much when I got it at 10 weeks, but I’m at 8 weeks again just now and it’s agony!

  8. Teresa says:

    Get yourself some sublingual methyl b12 tabs and take them to prevent the symptoms. They work as good as the shots, and are much more affordable.

  9. Lindsey says:

    For everyone on this thread, I recommend checking out the Pernicious Anemia/B12 Deficiency group on Facebook. It has loads of information and thousands of people talking about their symptoms and treatment. You do not have to have pernicious anemia in order to join the group. They talk about B12 deficiency caused by other things, as well.

  10. Ava says:

    I’m only 20
    and I have severe vitamin b-12 deficiency
    It was missed for years out of my blood tests and when jchanged GP it was noticed immediately
    I started getting injections there and then but a few months after my exhaustion had gotten worse and I had numb feet a sore tongue wasn’t extremely pale and constant pins and needles
    A full year after I got properly diagnosed with perperhial nerve damage I can barely walk
    My balance is so bad I’ve to get help to the toilet
    I’ve had so many falls and now getting a wheelchair
    I’ve bad degeneration of the spinal cord and don’t know if I’ll ever heal
    They are still investigating the cause but seen to think it’s a mixture of diet and stomach absorption problems as it runs in the family aswell
    Just said I’d share my story

  11. Teresa says:

    Are you also being treated for folate deficiency? Ask your doctor to test you. You might want to add methylfolate to what you are doing.

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