Judging by the lack of answers to your questions, I'm guessint that this is a totally new question, never been asked before, and nobody has any answers! It is certainly something I have never even thought about before.
For example if my B12 is low does that reflect my diet (or absorption) over the last week, month or 6 month period ?
Goodness! So, what you're asking, in effect, is how long do B12 levels take to drop? Hmmm... Well, as with just about everything else connected to thyroid, I would say: it depends. I don't think there are any clear cut answers, but many variables. For example:
* when you're hypo, you usually have low stomach acid, which makes digestion of food and absorption of nutrients difficul. So, if you're eating a 'normal' diet, some B12 is probably getting through, but not enough. So, that would be a slow-ish drop.
* If you're vege or vegan, you won't be getting any B12, so the drop will be rapid.
* if you have pernicious anemia, well, depends when the PA started.
But, not sure anybody could put a time-period on any of that. Days, weeks, months, years? Who knows? I doubt if much research has ever been done on the subject. I could be wrong, but I've never come across any information of that sort.
Also Calcium are these results related to diet, or to loss of calcium from bone which leaches into blood so not good?
Could be both. Also depends on the state of your parathyroids, the little glands situated around the thyroid, that control calcium, if they're healthy or if you're missing one. And then there's calcitonin. Never been quite sure what that does but it's produced by the thyroid and something to do with calcium control, so if you don't have a thyroid...
So, no, these are not basic questions by any means. I'll be interested to see if anyone can come up with some concrete answers.
These are not basic questions Spritze and I for one thank you for asking them.
I Googled half-life of B12 and this popped up. I’ve pasted the extract that appeared at the top of the results page.
Vitamin B-12 is absorbed in the lower part of the small intestine. It's highly bound to plasma proteins in the bloodstream. These are called transcobalamins. The half-life is about 6 days.
I found this info on the B12 and I think it is buried in a larger body of work in the reference below - I have yet to fully digest it myself, but I will be plugging through it over the next few days.
I know vitamin D3 and cofactor K2-MK7 are together important in directing calcium into the bones and away from the blood vessels where the calcium can create deposits, but I’m not sure if those deposits would have any presence in a blood sample. So more reading there! 😂
Iron is quite important for absorption of everything , but shouldn’t be supplemented if levels are already good and I think greygoose is very knowledgeable about spacing supplements so they don’t interfere with one another.
These are great questions and as we were sometimes told when at school by the more enlightened teachers, the only silly question is the one not asked.
If getting B vitamins get methylated versions these are more bioavailable.
I will tag SlowDragon In as she has oodles of info on Thyroid tests, supplements etc. it is a bit if an info dump - don’t be put off. Just a bit at a time. I can honestly say the forum saved my life - I was extremely ill when I landed here. Took advice, read and read - made notes read more, successfully advocated for myself with various doctors and I am well now. 😊👍
The healthy body appears to require only a tiny amount of B12 each day.
Most B12 is recirculated - very efficiently - but a little gets lost, somewhere around 3 micrograms every day.
Hence, the various recommended daily amounts, etc., are themselves a similar quantity.
Part of the recirculation is entero-hepatic. B12 goes into the digestion, gets re-absorbed, and sent back to the liver through the hepatic portal vein.
If anything at all disrupts that recirculation, the requirement rises, possibly dramatically.
This can include failure to separate B12 so that it can be linked to Intrinsic Factor and re-absorbed around the terminal ileum. Stomach acidity, various medicines, lack of Intrinsic Factor, all reduce absorption of B12 - and stop recirculation working.
The big lie about B12 is that we have months', years', worth stored in our livers. What we can actually store is enough to last a long time if a) we start out with plenty; b) we only lose 3 micrograms a day because recirculation is working well. It those are not true, then we lose B12, potentially quite fast.
Your B12 level is obviously affect by diet. If there is none in what you eat, you can't absorb any! But also by absorption and recirculation processes.
Other than stuffing the required supplements down my gullet to get the desired levels I just haven’t gotten round to this level of study. Now most of the boxes are unpacked I can see a bit more reading on the horizon. 😊👍
FOLATE - To be honest this is all too academic for me...... but if anyone is interested I have found this - pernicious-anaemia-society.... and I copy and paste this...
Serum folate. The serum folate concentration reflects recent folate status and intake......There is no clear consensus on the level of serum folate that indicates deficiency. Conventionally, clinicians have used serum folate lower than 7 nmol/l (3 lg/l) as a guideline because the risk of megaloblastic anaemia greatly increases below this level.
Red cell folate. The red cell folate level gives an assessment of the tissue folate status over the lifetime of the red cells and is therefore regarded as an indicator of longer term folate status than the serum folate assay. A red cell folate level below 340 nmol/l (150 lg/l) has been regarded as consistent with clinical folate deficiency (Jo- elson et al, 2007) in the absence of cobalamin deficiency. Whether serum folate or red cell folate is better for assessing body folate status has been extensively argued.
So it seems it is all very well doing blood tests but important to understand what exactly we are measuring ?
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It is certainly something I have never even thought about before. 
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