Delirium from B12 Deficiency

I have added another case of vitamin B12 deficiency to Individual Cases of Deficiency of Vitamin B12: Are You Getting It?

Readers have asked me to keep letting them know about these cases, so here it is:

A 62 year old woman in Switzerland, strict vegetarian, was found wandering the streets. Her delirium was determined to be vitamin B12 deficiency. She was treated with 1,000 µg injections weekly and within 4 weeks she had regained a stable mental status and returned to full-time work. (1)

It turns out that she had suffered from B12 deficiency on a number of previous occasions but without the neuropsychiatric symptoms. I hope she will start taking B12 and not rely on being found wandering the streets which might not end so well the next time.

(Thanks, Michael).


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1. Mavrommati K, Sentissi O. Delirium as a result of vitamin B12 deficiency in a vegetarian female patient. Eur J Clin Nutr. 2013 Jul 17. | link

11 Responses to “Delirium from B12 Deficiency”

  1. Michael Says:

    Yikes! I try and relate stories like this to vegan friends who don’t have a reliable source of B12 but to no avail.

    On a side note, I would be interested to know whether the woman in question gave up on vegetarianism or simply began taking a B12 supplement.

  2. Jack Norris RD Says:

    No indication that she gave up.

  3. Andreas Says:

    Good to know if I ever need to supplement.

  4. Dan Says:

    This is a remarkable story but not surprising (at least to a clinician). I used to tell my house staff to screen B12 in any person who came in over 60, and *particularly* if they had any cognitive issues whatsoever. The same goes for people under 60 with cognitive issues. I can remember one lady who lost the ability to walk and had an extremely low B12 of 78. Unfortunately, I do not know what happened to her after supplementation was begun.

    B12 deficiency should be screened in anyone with confusion, delirium, dementia, falls, neuropathy, unsteadiness, gait/balance problems, etc, regardless of vegan status. Doctors don’t tend to ask about vegan status anyway (it simply never comes up). I would bet there are far more clinical B12 deficiency cases in people who happen to be omnivores than in people who happen to be vegan, because there are multiple ways to get B12 deficiency rather than just decrease oral intake (achlorhydria, intrinsic factor deficiency/pernicious anemia, Crohn’s disease and other causes of ileitis, receptor issues, etc). Elderly people in general also tend to have poorer diets, especially those living alone, even if they are omnivores. They call these people ‘tea and toasters’, and they usually have multiple nutritional deficiency states.

  5. Gale Says:

    Hi Jack,

    I am wanting to switch to a methylcobalamin source of B12 because I have been having stomach issues and the B12 I am currently taking may be the culprit. Do you have a favorite? Many seem to have preservatives that are questionable.


  6. Jack Norris RD Says:


    I don’t have any favorite.

  7. Amanda Says:

    Whoa! I didn’t know that could happen. That’s scary.

    I know my levels are okay because I’ve had them tested (and I drink soy milk daily and have an unhealthy love for nutritional yeast), but I always worry that because of the “vegan as panacea” crowd, things like this will happen to my friends or people I “convert” to veganism. But that’s why I always try to share with everyone!

  8. Dan Says:

    A colleague (pharmacist) tells me that he gets all his vitamins from, because they specifically source to health care providers and strive to maintain a minimum of chemical additives.

    I am surprised that B12 would cause stomach issues, but I guess anything is possible. I have never seen this issue in many hundreds of people who take the standard B12 preparation.

  9. Gale Says:

    Hi Dan,

    Yeah I was surprised too. After researching it a bit I thought I would try the methylcobalamin and see if it made a difference.

    It seems the less supplements I take the better I feel. Surprise, surprise!

    Thanks for the source.

  10. Dan Says:

    I guess anything is possible (any drug or supplement can cause any health problem). Many side effects are idiosyncratic in this way. The main reason to prefer methyl over cyan is if you have diabetes or chronic kidney disease, as cyanide can accumulate in the latter groups. But give it a shot.

    I also prefer fewer supplements. Soon I will be down to B-complex and iodine only. I am considering adding vitamin A though, as peacounter suggests I am quite below the RDI for A.

  11. Gale Says:

    B-12 and iron (Blood Buiider) here. I run a lot so low ferritin levels are no fun.
    I am sure you eat your leafy greens?

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