There are two things I wanted to start a discussion on with regards to B12 dosing: folate and potassium. I'll start with potassium, because I think it's more important.
Many people on this board rightly advise newcomers to monitor potassium levels when beginning B12 supplementation. However, in my medical textbook under B12 supplementation the following warning is given:
"Hypokalemia and sudden death have occurred in severe megaloblastic anemia treated intensely. Serum potassium levels should be carefully monitored, and supplementation provided as needed."
I took a small dose of B12, unwittingly B12 deficient, as my labs did not reflect this. Within 7 hours I became exhausted, I had heart palpitations, and I passed out. I was only 25 years old. Luckily, I remembered reading the bit about potassium and when I regained consciousness, I took some and called an ambulance. Once at the hospital, they monitored my potassium levels and found they fell another 0.6 within a couple hours, while the B12 did it's thing. That is massive.
I needed very large doses to keep myself out of the hospital - 80meq per day. That is the equivalent of about 80 bananas. So, for people suggesting a banana suffice for potassium loss, I have to say I strongly disagree and potassium levels should be closely monitored when beginning B12 supplementation. Most, thankfully, won't react as violently as my levels did, but everyone should know that making new Rbcs and DNA synthesis requires a TON of potassium.
I'm too tired now to add the folate bit, but will do so tomorrow.
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rachelabc
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rachelabc - you would seem to be at a particular extreme - and I've never come across a similar case. It is likely to be more to do with the way your body processes potassium than the B12.
What exactly was the dose of B12 that you took and was it oral or injected?
I would not advise anyone to take the quantities of potassium you mention without medical supervision as in the vast majority of people they would lead to an overdose - hyperkalemia - which can be just as damaging.
It is not the way I process potassium; as stated, it is clearly documented in medical literature to occur in some cases of B12 depletion, due to rapid RBC synthesis.
Also, I did not recommend that anyone take such high doses of potassium. I gave my dose strictly as an example of what an extreme case looked like, and instead urged that people have their potassium levels closely monitored by a doctor.
The dose of b12 was only 1mg and it was taken sublingually.
The depletion of potassium due to rapid reticulocyte formation happens over days, not hours. So it’s extremely unlikely that yours was caused by that. emedicine.medscape.com/arti...
Reticulocytosis starts in 3-4 days and peaks at 1 week.
If your labs didn’t reflect a B12 deficiency how did you decide you were deficient.
If your labs didn’t indicate macrocytic anaemia then you wouldn’t have undergone any rapid reticulocyte formation. So it couldn’t cause and potassium loss.
That's actually not true Fbirder. We are actually taught in med school to closely monitor potassium levels after B12 repletion in those with severe deficiency for the first few days, as this is when the acute (and potentially dangerous) reaction will occur, if it is to.
Labs are not reliable indicators of B12 deficiency. There are several reasons that things like B12 deficiencies and anemias are masked, or missed, in labwork. Thus, B12 deficiency is to be treated based on symptoms and response to treatment.
And, on the topic of potassium: potassium *can* be dangerous - if you take too much at one time, have issues with kidney function or are taking medications which impair potassium excretion. The dosages mentioned in this thread are at the higher end for daily supplementation, but the dosage is not in itself dangerous. Nearly 50meq (from food) is the RDA, for the purpose of perspective. At 99mg per over the counter pill, it would take 50 of these pills to equal the RDA, let alone the 80 required for an 80meq dose.
I think the takeaway here is simply raising awareness for the fact that yes, in a small population of B12 deficient patients, a serious and life-threatening situation can develop upon initial repletion of B12 stores if potassium is not monitored and supplemented as needed. However, most people won't notice symptoms of potassium deficiency until after a couple weeks; this type of slower depletion is much less dangerous and easier to correct.
Well, there's a bit of a problem in that it's highly unlikely a person will get any medical advice or monitoring of potassium, folate, or iron while having B12 injections, and definitely not if taking an OTC tablet or sublingual. Maybe if you ask for it, or if you were in hospital, but otherwise I've never heard of anyone being monitored like this.
When I have a blood test for my diabetic screening I always have a potassium level measured. The last one (Monday) was 4.3 mmol/L - smack in the middle of the range. That’s a total of roughly 25 mmol or just under 1 g in total.
You're right, most won't. But, that's why it's important to be your own advocate and ask to be tested. If the doctor is supplying B12 injections, they should at least be aware of the interactions B12 has with potassium, and I can't see a reason for them denying this request for testing. As an aside, potassium shouldn't need monitored for longer than the first week; the first month would be ultra conservative and likely unnecessary. I guess if you made it past the first week of (high dose) B12 supplementation, you're likely in the clear.
I had mine at weekly intervals, not loading doses over a week, and was aware of potassium and the symptoms of low potassium so was watchful. My GP didn't bring it up. I would have asked had there been a problem. Needing extra or regular monitoring is one of the things that I assume would make getting B12 treatment more of an issue with the current pressures many surgeries are facing.
The one small banana a day is to ensure sufficient potassium in the Newcastle diet which is very extreme. It is a good insurance and works well with most people.
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