Pernicious Anaemia Society
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Advice about lack of B12 needed

I'd like to find out more about lack of B12. I've been unwell for about 7 years after surgery for thyroid hemithyroidectomy. I've seen lots of docs. I've felt like I couldn't breathe properly and waking at night gulping for air and in the morning waking feeling like I'm suffocatinng combined with aching from head to toe, my brain not working properly, numb hip and strange pains here and there, anxiety and feeling very low like everything is colourless. My blood test for B12 came back normal, folate was a bit low but normal for NHS. Vitamin D fine and ferritin ok. I started taking methylcobalmin with a B multivitamin and started feeling a bit better. I added methylfolate 400mcg. I increased the methylcobalain to 1500 mcg daily and feel a lot better. If I stop taking it I feel really ill. ANy ideas what's going on? Could I have a B12 deficiency? I have a really healthy diet with plenty of fresh fruit and veg, tried cutting out caffein but made no difference.

3 Replies

B12 only comes from animal products - so you need meat/fish/dairy/eggs to get it from your diet.

However, unless you are a really strict vegan who doesn't supplement B12 then a dietary deficiency is unlikely - most common reason for a B12 deficiency is absorption problems.

I would suggest that you get hold of the exact results for your B12 test - it's not a very accurate tests and misses a lot of people who are deficient - but then it is difficult to have an accurate test because people vary a lot in terms of the amounts of B12 they need in their blood and it isn't what is in your blood that causes the problems - its what is happening in your cells.

An absorption problem doesn't mean no absorption - the amounts of methyl cobalamin you are taking are enormous - about 400x RDA so enough to keep someone without an absorption problem going for over a year - though the mechanisms for storing etc are such that most of it would actually just pass straight through you. So, the tablets you are taking are probably just managing to give you enough B12 to start raising your levels a bit and provide enough at the cell level for the body to do all the things it uses B12 for - in conjunction with folate.

If you didn't have an absorption problem and the deficiency was just dietary then I don't think you would be continually needing to top up as your body would store and then be able to use the stored B12 from the tablet. However, with an absorption problem it affects the storage mechanism as well so you need to constantly keep the levels topped up which would explain why not taking the tablets makes you feel bad again


Thank you for your really helpful reply. I have my blood test results for B12 and it was near the top of the range so about 600 and so I didn't think it could be B deficiency except that nothing the drs suggested helped and some things made it worse. Then a friend who was a nurse said the symptoms sounded like B deficiency so I cautiously tested sublingual methylcobalamin and started to get better. Oh, I have a healthy diet with meat included and cook from fresh.

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My earliest result was just under range at 196 in beginning of 2016, and my latest was over 2000, but am having 2 injections per week now since October 2016, and yet my deficiency symptoms are all still with me: less extreme or less frequent, but none have completely gone. Not yet. Over the last 2 years, I've been tested for everything else it could possibly be, and only when MMA levels found to be high in October was "functional B12 deficiency/ insufficiency at tissue level" confirmed. I read that only 75% of B12 deficient people have Pernicious Anaemia*, which leaves an awful lot of people in the "other" box !

* Since most current means of testing this appear to be flawed, I wouldn't be so sure


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