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Pernicious Anaemia Society
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Folic acid

Hi every one.

I have b12 injections every 12wks. I have to supplement with the sublingual spray a month before my next ones due.

Three weeks ago my tongue became sore. I started folic acid 400mcg daily and I was cured within 2wks.That was a result.

My question is should I continue taking it.I do feel a lot better on it.

I look forward to your replies and thanks in advance.


8 Replies

The dose you are taking isn't flagged up as a dangerous dose. Usually the upper daily limit is set around the 800-1000mcg level, depending on where you are.

The main reason given by the EFSA (European Food Safety Authority is the risk that high levels of folate will mask the anaemic effects of an underlying B12 deficiency and as a result may lead to delays in diagnosis. However, that's a bit irrelevant given that you already have had your B12 absorption problem diagnosed.


You can get methylated forms but reactions to those - from what I have seen on this forum - are a bit mixed and if you have found folic acid helpful that rather implies that you don't have a problem converting to methylated forms, which would be the main reason for looking at a methylated forms.


Thanks gambit for that.


I know this isn't the question you asked but have you thought of asking your GP to give you injections every 2 months instead of 3?

I was on 2 monthly injections but was running out of steam the last 2/3 weeks and my GP was happy to move to monthly.

As far as the folic acid is concerned, on the basis that you're feeling better on it then the answer must be yes continue to take it. Some people would advocate a higher dose than what you're taking in any case.


Yes I have asked him for 2mnthly injections but he won't give an inch.Guide lines are 3mnthly he says.

I know I should persevere but at the moment I am good with the folic acid as well.

If I asked again I would have to have a blood test and then there is a chance he may stop them altogether if levels are high.

In other words I can't risk it !

1 like

Many, many of us can and will empathise and agree with what in all honesty is an appalling admission to have to make "I cant risk it!"


Yes I know it is apalling but what else can I do?

If necessary I will go down the route of buying my own.

Thanks for your concern.


Get some 1000mcg methylcobalamin tablets. They're about USD$15, which probably translates to like 10 GBP. Try them once a day for a week or two and see how you feel. If you feel weird then don't take them.

I agree with Gambit about the folic acid, too. 400mcg is not a lot; its the RDA in the US, and you'd get that from a bowl of Corn Flakes and a piece of toast. Its not enough to really build up any unmetabolized product, either. So try 1000mcg of methylfolate, as well, and see how that makes you feel. Again, if you feel weird, you don't have to take more.

In either case, you should make sure you're getting potassium and lots of magnesium. You can supplement 99mg of potassium (when you take the b12) and 300mg+ of magnesium (before you go to sleep), or eat a salted avocado and/or an orange and/or a plate of salty braised greens every day. When you fix the b12 depletion your body is going to start producing a lot of cells, and that production requires lots of minerals. You can end up feeling like you have the flu, but most of that is the potassium deficiency. So make sure you're not potassium deficient before you decide whether you feel weird or not.

The b12 supplementation regime in the UK, US and Canada is premised on providing the bare minimum to literally support life. I'm not sure why its so low... maybe they think more would make us soft, or something? But now that you've gotten the bare minimum, you can start to make some tentative efforts to feel better.


"Guide lines are 3mnthly he says."

If you have neurological symptoms (see symptoms lists below) then the BNF (British national formulary) Chapter 9 Section 1.2 and the "BCSH Cobalamin and Folate guidelines" suggest maintenance doses every two months.



See Symptoms Checklist. I printed a copy of this, ticked all my symptoms and gave a copy to GP.

I gave my GP a copy of the BCSH Cobalamin and Folate Guidelines. All GPs will have access to the BNF, there is probably a copy sitting on the GP's bookshelf. Not all GPs are aware of the BCSH Cobalamin guidelines as this is a relatively recent document (2014). I was told that the NHS should be following the BCSH Cobalamin and Folate guidelines.

Its possible that the regional NHS guidelines on B12 Deficiency Management for your NHS area have not been updated since the BCSH Cobalamin Guidelines came out. These regional guidelines may be found by an internet search, a search on local NHS website or a FOI request to local NHS website. Your local CCG , if you are in England, may be able to tell you if your regional NHS is following the BCSH cobalamin Guidelines.


If your GP does not know about teh BCSH Cobalamin and Folate Guidelines, he/she may be able to get help from the county/area haematologists at the main hospital.

This link contains similar info to the BNF about treatment. See Management section.


How many loading doses did you have when first starting treatment?As I understand it B12 deficiency patients with neuro symptoms should have more

than the standard 6 loading doses.


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