Can high serum B12 ever become toxic? - Pernicious Anaemi...

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Can high serum B12 ever become toxic?

3 years ago•2 Replies

I have pernicious anemia and also beriberi due to prolonged thiamine deficiency. I am prescribed methylcobalamin and thiamine hcl injections. My primary care recently checked my serum B12 and asked me to stop B12 injections because my levels are at 702,173 pg/ml and she believes this is dangerous. Has anyone else had levels this high? I've been told my high serum B12 is related to my thiamine issues. Thiamine is a cofactor in the Kreb's cycle, which creates ATP, and ATP activates cellular uptake of B12, so without enough ATP, B12 accumulates in the bloodstream in its unusable form. I had been injecting an average of 2,000 mcg of methylcobalamin every 2-3 days before stopping B12 injections for the past month. I've started getting ringing in my ears again and feeling cognitively impaired since stopping injections. Not sure if I should ignore my doctor's toxicity concerns and resume injections?

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HealingRose

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fbirder3 years ago

You asked a similar question two months ago, except then your very high levels were only 70,000.

" so without enough ATP, B12 accumulates in the bloodstream in its unusable form. "

Nonsense. If you were that short of ATP you would be dead. It is used for just about every bolidly function.

"my levels are at 702,173 pg/ml and she believes this is dangerous. Has anyone else had levels this high?"

No, That is 702,000 ng/L - No assay I know of can measure levels that high. They normally top out at 2,000 to 6,000 ng/L.

There is no known harmful level of B12. stichtingb12tekort.nl/engli...

Gambit62Administrator3 years ago

Conversion of ATP to ADP with the release of energy is the key way that cells release energy.B12 is also needed for the Krebbs cycle to work.

I have not heard of anything that points to ATP playing a part in cellular uptake of B12 and find it extremely unlikely that this compound to be involved in anyway in 'cellular uptake' of B12. Unfortunately serum B12 isn't a good guide to whether you have enough B12 post injections - and you really need to listen to your symptoms which do indicate that you could go back to more frequent injections

Toxicity of B12 is a load of rubbish - if it were then they shouldn't be giving B12 injections at all as an injection puts your serum B12 levels well over the top of the measurable range and they then fall over time.

Please note I am closing this post to further responses