How serious is b12 deficiency? - Pernicious Anaemi...

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How serious is b12 deficiency?


Couple of weeks ago I went to my gp after getting pins and needles and numbness symptoms down my left side and suggested to her this could possibly be thyroid issues so had a blood test done and got a phone call from the receptionist a week later to pick up a prescription was never told what it was for. When I got the prescription I typed the cyanocolbalamin and folic acid into Google and found pernicious anaemia I was very concerned as everything I have read suggests this is quite a serious condition and even more uncommon in my age group of 25 since then I have been noticing other symptoms like grey hairs and thinning hair also heart palpitations as well as the pins and needles all point to this condition. Just looking for some information because I haven't actually spoken to a doctor or been told this is the actual condition just given the medication and it is making me very concerned :(

17 Replies

Dont panic!

Ask for an over the phone appt with your gp to explain why you have been prescribed cyan. Then go and visit if you feel the explanation and medication you have been given isnt working to address the symptoms you have described.


Quite possible that you may not get any useful information out of your GP - there is a load of stuff on B12 deficiency on the PAS web-site - which you can get to by clicking on the PAS logo on the page headers underneath the green HealthUnlocked banner.

I was diagnosed as having low B12 in hospital when I was in to have a broken ankle pinned - it was a teaching hospital and the surgeon asked the students what B12D was - all I really picked up from that was irregular bowel movements. Took me another 6 months to work out what was going on - and another 9 months after that to work out how I really needed to be treated.

B12 deficiency is a serious illness but it is also one that is very easy to remedy - B12 isn't expensive relatively speaking. It isn't toxic so you can't overdose so, in theory a lot easier to treat than something like diabetes or thyroid ... however, the downside is a battle against general medical ignorance and misconception.

Unfortunately vitamins aren't necessarily part of the syllabus for doctors

B12 deficiency is a killer if left untreated. B12 is used - in conjunction with folate - for cell reproduction (which is why it leads to a type of anaemia in which red blood cells are deformed and work less efficiently), and also helps to maintain the lining around nerve cells that insulates them - hence the tingling etc.

It sounds as if you have been given tablets to take. Generally the cause is an absorption problem so tablets may not necessarily work - 99% of B12 is absorbed in the ileum so you would need to be taking over 100x RDA to be getting enough - and if you are showing signs of deficiency you need more than this to maintain levels.

Normally it is stored in large quantities in the liver and then released into the ileum for reabsorption - so if you have an absorption problem a) it can take a while to develop into a full blown deficency - years or even decades and b) you won't be able to store and recycle B12 anymore.

Its only found in animal products - though fish and dairy are generally more readily absorbed than b12 in meat - so strict vegan diet would lead to a deficiency.

However, much more common causes are absorption problems such as a) autoimmune responses that attack the mechanism by which B12 is absorbed in the ileum, b) lowering of stomach acid levels - generally as you get older ... IBS is often another manifestation, c) gastric surgery affecting the ileum, d) drug interactions - ironically including many drugs used to treat what can be warnings of a pending problem - such as PPI used to treat acid-reflux, pain killers such as NSAIDs .... as well as others such as metformin used to treat type 2 diabetes.

The onus should be on proving it is dietary rather than assuming it is dietary - hence the suspicion that you have not been given the right treatment.

It is possible that high doses orally (1-10mg a day) may work but it certainly isn't the case for everyone.

You need folate in order to process B12 so good to keep your folate levels at the high end of the scale. Best source for folate is food - if you can ... though there are some genetic conditions that can affect peoples ability to process folate from food - but suggest that you look at your diet and try and identify changes that would increase your folate intake if possible - fresh fruit and vegetables.

Don't know if you are based in the UK - if so then you might want to draw your GPs attention to the BCSH guidelines - which are treatment by injections of 1mg of hydroxocobalamin administered intramuscular.

a) loading shots every other day for 2 weeks (if no neurological involvement) or until symptoms stop improving (which should be the protocol in your case as you mention pins and needles) - with a review after 3 weeks.

b) maintenance shots ever 3 months (no neurological involvement or every 2 months if neurological involvement

So, for you it should be every 2 months for the maintenance shots.

(page 8 I think).

Having said that though lots of people find that 2 months isn't sufficient for them.

Some books:

The B12 Survival Handbook

Could it Be B12?

and there are number of books that have been published by the PAS

These sites may also be of interest


Xxvickieexx in reply to Gambit62

Thank you for the great info :) i am

Hoping to make an appointment with my gp asap quite annoyed with them not telling me what the medication is for. Just checked my dose of the cyanocolbalamin and it is 50mg is this a high dose? I have been googling many of the symptoms and am quite concerned but I think my doctor will dismiss my claims however I will be sure to ask her thanks again :)

Gambit62Administrator in reply to Xxvickieexx

Anger is understandable nut reality check is probably the reason why you haven't had any information is because GP probably doesn't really know what they are treating ... they probably think it is a rare condition (depends on what you mean by rare - incidence is comparable to diabetes). They are generalists and as said above, vitamins probably weren't covered adequately in their training.

The amount you are being given is unlikely to have any real affect as it is only 2x the RDA, so would only be suitable if the problem was dietary - and from the conversation with fbirder it sounds as if the problem you have is an absorption problem rather than dietary. Depending on how many tablets you were given and assuming that you pay for prescriptions you could probably get much larger amounts from the chemist at less than what you paid for the prescription.

It would be useful to get a copy of the test resuls that were used for the diagnosis - there might be a charge for this but the GP should be able to just print them off. It is likely to be a long test and probably includes indications that you have anaemia (enlarged deformed blood cells - a classic symptom of B12 deficiency ... but it is just a symptom.

It is also quite likely that your GP is totally unaware of the range of symptoms that are caused by B12 deficiency and as some of the guidelines - eg NICE are quite poor in their presentation - may be treating it as a blood disorder rather than a far reaching problem that spans many medical disciplines.

The NICE guidelines do talk about establishing the cause of the deficiency but personally I think they should talk about establishing whether or not the deficiency is dietary in origin as this is the only differentiator in terms of the correct treatment. The tests for potential causes of B12D focus on pernicious anaemia - an auto-immune response and none of the tests are accurate enough (IFA can be done several times before revealing a positive result as it just isn't sensitive enough). The choice is between relatively low doses if dietary (eg the 2xRDA you have been prescribed) and extremely large doses if there is an absorption problem but that just doesn't come through in the guidelines.

Thne guidelines also focus on B12D as a blood disorder - hence referal to a haematologist - when actually it can affect other systems in the body (neurological/neuropsychiatric) and these can manifest themselves before any evidence appears in bloods.

There is also some confusion over treating combined folate and B12 deficiencies and a lack of clarity that can treat to B12 being treated without folate (B9) being treated. It is important that BOTH are treated simultaneously as B9 is needed to process and use B12.

Are you sure it's 50mg and not 50ug (or 50 mcg) which is 1000 times lower. 50 ug are the only tablets licensed for use by the NHS and, assuming you have an absorption problem, are totally and utterly useless.

Xxvickieexx in reply to fbirder

Sorry they are 50 micrograms to be taken daily along with 5mg of folic acid. I wasn't told why the doctor was giving me these I have just checked the names online and it says a b12 deficiency. Would you suggest I ask my doctor for a different medication ? Thanks

fbirder in reply to Xxvickieexx

I would suggest that your doctor follows the guidelines given by the British Committee on Standards in Haematology- see Gambit62's post above.

They also should read the NICE guidelines - - which says that the doctor should determine the cause of any B12 deficiency.

It sounds as if your doctor has decided that it would be easier (for them) to assume there's no absorption problem, and to give you tablets. If you're not a vegan then this approach is almost certainly wrong. The tablets will do nothing to help you and you will continue to get worse.

Pernicious Anaemia is serious (look up 'pernicious' in the dictionary). One of the deadly effects is called Sub-Acute Combined Degeneration of the Spinal Cord, which is likely to happen if proper treatment is delayed.

See your doctor. Insist on treatment described in the British National Formulary (your doctor will have a copy) and testing for anti-Intrinsic Factor antibodies.

Xxvickieexx in reply to fbirder

I also thought this strange as I am not vegan and would say have a balanced diet thank you hopefully she will look into it.


I've assumed you're in the UK.

" am not vegan and would say have a balanced diet"

Are you vegetarian? it is more difficult for vegetarians to get adequate B12 in their diet although not impossible as dairy and eggs are reasonable sources. If you are neither vegetarian or vegan and eat a diet with B12 rich foods such as dairy, eggs, meat, fish, shellfish then it might be worth looking into whether you have an absorption problem.

Have you ever been tested for Coeliac disease?

List of causes of B12 deficency

Do you know your actual B12 results? Also folate , ferritin and FBC (Full Blood Count) results? I learnt from experience to always get paper copies of my test results as what I was told was not always what was on the paper copy.

Tests that can help diagnose B12 deficiency. A blood smear aka blood film may also be helpful as b12 deficiency can cause shape changes in some blood cells

I am surprised that your GP has not given you an IFA (Intrinsic factor antibody) test which can help to diagnose PA but does not always give reliable results. People with negative IFA test results can still have PA. Is there a family history of B12 deficiency/PA?

You might find it helpful to contact the PAS. If you leave a message they will get back to you.


01656 769467

Office open 8am till 2pm every day except Sundays....some changes over New Year.

Early greying and heart palpitations can be symptoms of B12 deficiency. See symptoms lists below.


Symptoms Checklist

As Gambit says B12 deficiency can be a killer. Inadequate treatment could mean permanent neurological damage and severe mental health problems.

useful documents/articles/books

Gambit mentions the BCSH Cobalamin and Folate guidelines. I read the whole document and gave a copy of to my GP. I found page 29, a diagnosis and tretament flowchart useful.

Are you on any other medication? See drug induced causes in link below.

Have you had any surgery involving nitrous oxide recently?


What You Should Know About Pernicious Anaemia and Vitamin B12 Deficiency

by Martyn Hooper

Could It be B12? by Sally Pacholok and JJ. Stuart

Martyn Hooper is the chair of the PAS and has written several books aout b12 deficiency and PA.

Good luck with finding answers.

clivealiveForum Support

Hi Xxvickieexx ,

I was diagnosed with P.A. at the relatively early age of 28 and was put on monthly 1mg cyanocobamalin injections but in my case it was due to having had gastric surgery for a perforated peptic ulcer at the age of 17.

Above are some very informative posts from people far more knowledgeable than I with brilliant advice so all I want to say to you is - whatever the cause of your B12D is, as lisahelen says "Don't panic!", list your symptoms, print off authoritative extracts from the medical sources you've been given links to and present them calmly to your G.P. Hopefully she will learn from them and you will get the treatment you need.

As has been said elsewhere P.A. (if you do have it) and B12 Deficiency are both easily treated and I'm still "clivealive" after 44 years of injections at my local surgery and am now coming up to the age of 75.

I wish you well for the future.

If you were tested for thyroid issues it would be interesting to know the results with ranges. I cannot add to the excellent information given to you above about B12 - but would like to say the medical profession is equally bad at testing the thyroid as they are B12 Deficiency/PA.

You would need the full profile testing - TSH - FT4 - FT3 - and the anti-bodies - Anti-TPO and Anti-Tg. If you do have PA which is auto-immune then it is possible to have auto-immune thyroid illness too. Auto-immune conditions often hunt in packs !

If your GP will not oblige with thorough testing then it can be done privately......

Hope you soon get the treatment you deserve....

If I were you I would see a doctor as soon as you can to explain it and they can give a formal diagnosis. its a lifelong condition that is manageable by injections. You also need to be sure s/he has fully documented the symptoms. A charming have you got it all down Dr because it worries me will help.; my husband swears by writing a letter. its on file and they tend to respond. Good Luck and Happy New Year.

Start a logbook of all your symptoms. Try to establish a severity score for each of your symptoms. Each person has different symptoms to different degrees of severity.

Pins and needles is one of the neurological symptoms and you should be getting loading doses via injection. This is typically 1 a week for 6 weeks. Then the typical regime for cyano is monthly but you may find you need it more frequently and the logbook will help show this to your GP. I'm on weekly cyano which I self inject.

Once you start on B12, other symptoms show up. These are from the rush of metabolic byproducts produced by the cells of the body once they get B12. They will quickly use up other vitamins and minerals so you'll also need a daily multivitamin. I also take a vit B6 supplement to support repair of the nerves.

The nerve repair is extremely slow but by looking back in the logbook you will see progress.

Nerve damage is very serious. Memory issues and probably the most debilitating.

Also be aware that as the nerves heal, the brain will get a stronger signal which might manifest as aggression or pain. Pain is good as it tells you that your body is healing.

Start gentle exercise to stimulate the nerves that need to be repaired. Getting started is always the hardest but once you get going things will get easier.

Discuss your plan with your GP. You are going to be going through a period of experimentation about what combination of vitamins and supplements works for you.

You may also notice that some symptoms occur 6 to 24 hours after eating or drinking something. This delay is because the gut is involved. When a new symptom appears, look back at what you did or ate yesterday. Keep a record of food and drink in your logbook.

If you suspect a particular food issue, stop eating it for two weeks to allow the liver and bile to completely detoxify. Then reintroduce and monitor your symptoms for 48 hours to see if any in you logbook correlate to that food item.

Some people develop gluten and dairy (casein protein) intolerances.

Keep your GP informed. He may treat you as a hypochondriac. Just don't let him prescribe an antidepressant for an anxiety disorder. Anxiety and depression are two more neurological symptoms of the b12D.

fbirder in reply to pvanderaa

Being as she is based in the UK the loading doses are every other day, the maintenance dose is every 2 months and she'll be given hydroxocobalamin, not cyanocobalamin.

Exercise doesn't stimulate the nerves.

50 ug of cyanocobalamin is practically insignificant. I supplement with 5000ug 2x methyl cobalamin on a daily basis in addition to weekly injections of cyano-b12 just to keep a clear head.

The 5 mg of folic acid is also the maximum daily dosage. Discuss the disparity between the two prescriptions with your GP.

There is also a concern that folic acid masks the B12D. You need B12 first and then a balancing amount of folic acid to support metabolism in the cells.

Use your logbook to determine the balance that works for you.

Also once you start B12 supplements or injections, blood tests are skewed and GP think you are "better" and remove the medications.

Also get a copy of your blood results.

Did you recently have any dental work done, a pregnancy, or medical procedure where anesthesia such as nitrous oxide was used?

Thank you, no no procedures have been done and last pregnancy was over 4 years ago now. Only symptom I went to doctor about is the pins and needles and numbness down the left side. Although I have recently noticed other symptoms I've had that I've not connected until now I have had hair thinning and noticed grey hairs even though I'm only 25 also some breathless ness when sitting and dizziness when standing up as well as noticing palpitations more often. Is it possible for symptoms to be more noticeable once taking the medication? Have had alot of dizziness today. Thank you everyone for the very good info will be sure to ask my gp soon as I can get an appointment hopefully there will be no resistance to test further.


Nobody that I am aware of has actually managed to establish a causal relation between premature greying and B12D. what has been observed is a noticeable correlation between the auto-immune condition that is PA proper and premature greying - same is also true with having blue eyes, ie indication of a genetic link with premature greying and blue eyes.

Given that the most likely cause of your B12 deficiency is an absorption problem, and given that the amounts you are being prescribed for B12 are woefully inadequate and not going to have any significant impact on your B12 levels it seems unlikely that that is a factor in the symptoms.

Other possibilities are heightened anxiety (a symptom of B12 - though one most medics are totally unaware of).

I really don't know if it could be something to do with the levels of folic acid - and I really don't know if that can cause potassium levels to drop - know that B12 can but back to the levels you are getting being pretty insignificant.

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