Hi Folks. A few quick questions? I have read differing messages from various messages here, and from clinical papers on whether we can eventually hold b12 "stores" in the liver? Or is it held within ones metabolic system?
It seems to me that some people can hold on to their b12 supply in their internal metabolic engines ( or livers ) for a few days....others for weeks...and months...?
B12 is stored in the liver .It takes years to deplete.
The mistake many gps make is the assumption after loading thst we can use it from the stores .
The process that is used to absorb b12 into our cells is obviously broken if the same b12 rich food is eaten and on no medications to deplete it .
So if wd have b12 deficiency the process is broken using it from any stores in the liver.
It's used directly from b12 circulating in our bloodstreams from an Injection.
Hence needing a regular supply.
If B12 deficiency is caused by a vegan diet or from alcohol abuse or from a medication .
B12 eaten or injected or b12 tablets will replenish stores.
The process works of utilising it.
My friend replenished b12 stores via b12 injections prescribed .
Changed her diet and doesn't need any b12 injections now.
Obviously dietary .
She used what was there up and wasn't replacing it.
An absorbtion problem or PA cannot utilise b12 stores in the liver.
That's how I understand it.
I haven't got the original, but search for "THE ENTEROHEPATIC CIRCULATION OF VITAMIN B12". It can explain things much better than I can.
Nakapan has it right. B12 from liver stores is released through the bile duct into the small intestine. With advanced PA, NO Intrinsic Factor, NO uptake. It just passes through. You can fill that liver tank all day and it does you no good. I too have had doctors tell me, erroneously, that once we get enough B12 into the liver stores I can go some time between injections.
Thank you Rexz. It's good to have the clarification. Good of you to take the time 🌻
The majority (>50%) of B12 is stored in the liver (1–3% methylcobalamin; 60–80% adenosylcobalamin) with total stores reaching up to 5 mg (ref1). 30% is stored in muscle (ref2). I believe that liver storage cannot be mobilized in the case of PA since the liver secretes ~ 1-3 mcg of B12 into bile where it is mostly reabsorbed in healthy people (ref1 and ref3). In PA this secreted B12 would be lost due to lack of intrinsic factor.
ref1 : E. Laird, A.M. Molloy, in Reference Module in Biomedical Sciences, 2014 available online at sciencedirect.com/topics/bi...
ref2 : Messina M, Messina V. The Dietitian’s Guide to Vegetarian Diets. Gaithersburg, MD: Aspen Publishers, Inc., 1996 via veganhealth.org/vitamin-b12...
ref3 : veganhealth.org/vitamin-b12...
See also my B12 absorption and transport primer:
healthunlocked.com/pasoc/po...
Some of the information from veganhealth seems conflicting or I am not understanding it properly. It presents two B12 bile secretion/absorption scenarios:
(1) "Various studies have indicated that .1-.2% of the body’s B12 pool is lost per day; the .2% loss occurs in those with pernicious anemia (5) (see below for an explanation of pernicious anemia). The average nonvegetarian stores 2,000-3,000 µg B12 (5), while losing only about 3 µg/day"
(2) "People normally secrete 1.4 µg/day of B12 into their small intestines via their bile (5). Consequently, healthy people can reabsorb about .7µg B12/day from their bile"
Reading this, combined with the account from Reference Module in Biomedical sciences leaves me confused with three scenarios. Do we secrete nearer to 10mg a day, 3 mcg a day or 1.4mcg a day? Let me know if you see a clearer answer as to whats going on here or if my reading comprehension is lacking!
My guess is that the 10mg figure from the ScienceDirect link is wrong. it says 10mg day -1(superscript) so maybe they mean 1mcg a day. Mobilizing 10mg a day would be impossible since total B12 stores in the body are less than that.
As ever, spot on. Thanks vm Technoid. I am getting the picture. I think! If I may? A follow on. .
In terms of the upper limit held in the body, wherever. Is there an upper limit for B12 load ? As it's water soluble, I have also heard you can't overdose? Is all excess weed away? If so, that suggests an internal regulatory process...? I am just looking at all the safety aspects of using b12 hydroxo. Which I am not using btw. Thanks in advance. K 🌻
Yes, once liver and muscle stores are full and the binding capacity in the blood has been exceeded, additional B12 will be excreted. This can happen in very large regular doses, for example your pee may turn pink if very large amounts are being excreted. Ask EllaNore about aha. There is no tolerable upper limit and toxicity has not been demonstrated at any dosage. In treatment for Cyanide poisoning, very large amounts are injected (thousands of times higher than deficiency treatment) and in this case the volume of fluid itself can be a consideration and would require monitoring. Even in such cases, usual side effects are pink color to face/neck and urine turning pink, maybe acne, but no long-term issues. You wont even approach this dosage with every other day injections so its not really relevant except to understand the very high safety level of B12.
Dont think that water-soluble means you cannot overdose on something. B6 is water-soluble but its possible to overdose if you take more than 25mg a day for a long period. Neurological damage can occur at 100mg if taken for a long period.
Thanks to the clarity of that explanation. I get it and take it on board Technoid. 🌻
I am pressing my GP to do an MMA and/ or B12 active. But he says they are not allowed. But the Phlebotomists let slip there was a way if needed. If he doesn't cave, I have sold my exercise equipment 😆😆. To get some done.
The game plays on...
My GP got an MMA test for me but had to try 3 different major hospitals. Once found to be raised, the hospital laboratory confirmed my GP's diagnosis of functional B12 deficiency.
B12 serum level were very high as B12 treatment had started, renal problems as cause for raised MMA ruled out by blood test, and later SIBO also ruled out by breath test and trial antibiotics.
Later, haematologist tested MMA four times with same result. Active B12 high. Homocysteine normal.
Later still, DNA specialists tested again for a 6th time - and MMA level was in normal range. This was three years and many, many B12 injections down the line.
All of these tests were NHS funded.
Thank you Cheryl Claire. Very good of you to let me know. I suppose I am putting off a confrontation of sorts with my GP. 😬
I don't know how to surface that he is resisting getting the specific tests like B12 active.. etc.
Also ...hey, by functional B12d diagnosis.. that means not test evidence supported...?
🌻
According to professor Ebba Nexö (one of the leading experts on b12) the b12 Storage in the liver lasts Max 1-2 years. Previous info (3-5 years) is a myth according to professor Ebba Nexö. This time can be much lower caused by medicines, operations, sickness, PA, GBP, genetics, no gallbladder and more.
Thank you Peder. It's a true mine of help and info in here 🌻.
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