High active B12 without supplementing

[emmagh26]

Hello

I was hoping somebody might be able to help, or provide assurance please? Back in February I was feeling so ill - fatigue, apathy, headaches, neurological issues, pins and needles (had these awhile), cold hands and feet, low body temp, struggling to lose weight (I have an underachieve thyroid which is medicated with T4 & T3), depression, anxiety, zero libido, dry mouth - I could go on and on. My Granny had pernicious anaemia and it looks v likely that my Mum did too, although she's passed away now, so there's no confirming. Anyway, I went to see a private GP who referred me to an endocrinologist as my cortisol level was on the low side of normal in the morning. The end ran a plethora of other tests, including B12 at my request, as I was convinced I had some kind of B12 deficiency going on. My iron and ferritin were also at the bottom of the range at 21 and 11 respectively. In the interim waiting for the B12 and other results, I started supplementing and having B12 shots and started on iron supplements too. Within a week/ten days I started to feel better and nearly all of the symptoms above started to resolve / disappear - I'd even started to lose weight! I then had my follow-up with my endo and found out that I had high active B12 (158) without supplementing, bar maybe a week or so the previous month and eating marmite! I then stopped the B12 injections (I've had 6 in total of hydro) and also any B12 supplements.

I was obviously concerned as I know it can be a marker for blood cancers etc, so at my follow-up with my GP last week he re-tested the B12 levels and the active was over 200. I haven't had any shots or taken any b12 since 14th March - so 4 weeks of nothing. Would the higher active b12 result be only because of the shots / supplements? I am feeling much better, although in the last week or so a lot of the symptoms have come back, esp the anxiety / teariness / depression and the weight loss has stalled and is creeping on - without a change in diet, so do some people need significantly higher levels of B12 to feel well? I'm a heterozygous carrier of genes MTHFR C677T and some other MTR, MTRR and COMT.

Any help / insight would be so appreciated. I'm worried that it could be a sign of something more sinister, but am hoping I just need higher levels of active b12 to feel well. This is the first time I've ever had B12 tested. All other tests FBC, ESR, CRP were normal. My GP wants to retest my levels in July, but am not sure I want to be off B12 for that long, as I really do feel better when taking it. Thanks so much!

[Gambit62 Administrator]

B12 from an injection will stay in your blood for quite a while - on average 2 months for hydroxo and 1 month for cyano - but they can vary a lot.

Basically the results one month after an injection isn't enough time to provide a real baseline - you need at least 3 months and in some cases it can be significantly longer.

The evidence from the active B12 tests is that you don't have a B12 absorption problem so don't have PA.

That doesn't necessarily mean that B12 isn't an issue - and it is possible that some of the genetic variants that you mention could mean you need higher levels of B12. It may also be the case that having had an injection you now need much higher levels of serum B12 than you did before - and that doesn't seem to be something that is related specifically to PA.

[Hanneke12 in reply to Gambit62]

Dear @Gambit62. You seem to know a lot about PA and B12D. One thing you wrote worries me: "It may also be the case that having had an injection you now need much higher levels of serum B12 than you did before" - what do you mean with that? I.e. can SI be addictive in a way??

[Gambit62 Administrator in reply to Hanneke12]

definition of addiction is continuing with a behaviour despite knowing that it is harmful.

it isn't something I think applies to B12 as B12 isn't toxic. The reason why some people react to high serum B12 in a way that seems to make the process that allows B12 to pass from blood to cell less efficient so they then need to maintain much higher levels of serum B12 to function properly isn't understood. However, it is a biological phenomenon. It isn't something I think fits into the characteristics of an addiction.

[Hanneke12 in reply to Gambit62]

Ok, phew. This I knew, that some people SIMPLY NEED more B12 in their blood to keep symptoms at bay. And I didn't mean 'addiction' in that sense. I thought I read that injection B12 could CAUSE that one needs higher levels of it in their blood... Did not mean to imply that injecting B12 or having high serum levels is a negative thing (I know from experience that it is not!)

[emmagh26 in reply to Gambit62]

Thank you so much for taking the time to read and get back to me and providing some reassurance. I think I'm one of those people who need high levels of B12 to feel normal, as without supplementing and no injections, I'm starting to feel worse again....Just need to decide whether to wait until another baseline test in July or to start supplementing again? Thanks again for your insight. Best wishes.