Up to 80% of a.blood serum reading for B12 can be inactive !

[wedgewood]

l know that read this somewhere . but can’t remember where . .Is this true and if so has anyone got a link to the source ? Thank you .

[Narwhal10]

O'Leary F & Samman S (2010) Vitamin B12 in Health and Disease. Nutrients 2(3) 299–316.

5th paragraph of the whole thing. 3rd paragraph under 1. Vitamin B12 Function.

ncbi.nlm.nih.gov/pmc/articl...

‘Serum vitamin B12 is bound to proteins known as transcobalamins (TC). The majority of the vitamin, approximately 80%, is transported on the inactive TCI (also called haptocorrin).’

This article does not state about 80 % of vitamin B12 being inactive but it does say how common the illness is yet, underdiagnosed.

Wentworth B J and Copeland A P (2018) Revisiting Vitamin B12 deficiency: A Clinician’s Guide for the 21st Century. Nutrition Issues in Gastroenterology. Series #182.

med.virginia.edu/ginutritio...

[PhilAB]

Yes, this is true my friend.

Also just 24 hours after Injection 80% of b12 has gone. This is why NICE say every other day injection, but they keep quiet on why.

[Nackapan in reply to PhilAB]

Also discussion on b12 serum blood test. So result say 100 only 20 % is usable by body ?

[wedgewood in reply to Nackapan]

Thanks Nackapan

[am111 in reply to PhilAB]

I think these figures are for cyanocoblamain. Hydroxocobalamin retention is much higher. Please see this:

ashpublications.org/blood/a...

[Technoid]

First some definitions:

Transcobalamin II is the only transport protein "car" for B12 which all cells can accept.

Conversely, B12 carried on the Transcobalamin I/Haptocorrin "car" can only be accepted by certain liver cells.

If B12 is being carried on the wrong transport protein "car" for that cell, the cell will have no way to accept it.

"HoloTC"(HoloTranscobalamin) is just the name for B12 when it's on it's Transcobalamin II transporter, the one which all cells can accept.

Confusingly, you might sometimes see Haptocorrin referred to by its older name, Transcobalamin I so, for clarity, in the quotes below, when they mention Transcobalamin, they mean Transcobalamin II.

"Transcobalamin (TC) binds most of the non-haptocorrin-bound vitamin B12 in plasma, i.e., 10%-20% of the total."

...

"HoloTC is taken into cells by receptor-mediated endocytosis. The membrane-bound TC receptor occurs in all cells"

...

"plasma haptocorrin appears to have no receptors on most cells and is bound only by asialoglycoprotein receptor in the liver. These facts suggest that it is not essential for vitamin B12 metabolic activity and may, instead, function to bring inactive corrinoids and cobamides (which are not bound by IF) to the liver for disposal."

From the chapter "Vitamin B12" in the book : "The Vitamins: Fundamental Aspects In Nutrition and Health, Sixth Edition" (Gerald F.Combs, Jr and James P. McClung), 2022

[wedgewood in reply to Technoid]

Thank you very much Technoid .It’s important to have the science explained .

[Beckburybelle in reply to Technoid]

This is brilliant. I would love to study Vitamin B12 more in-depth it fascinates me.

[wedgewood in reply to Beckburybelle]

We need the medical profession to study it too ! I wish that it fascinated them !

Yes it’s complex .

[FlipperTD]

Don't panic. [Scientist, not medic.]

B12 is transported by proteins traditionally referred to as 'transcobalamins'. The majority is carried by haptocorrin; typically about 75%-80% of the total, and the remaining transcobalamin fraction is the active part. Typical lab B12 assays measure total B12, and have done since we developed the tests. More recently, the 'active B12' test was developed, and this just measures the 'holotranscobalamin' fraction, but it doesn't mean that there's anything wrong with the traditional B12 assays. It just measures total B12.

[boisland]

wedgewood: link states: Only 6-20% of total plasma vitamin B12 is in the active form, bound to transcobalamin II.. bmj.com/content/349/bmj.g52...

[Narwhal10 in reply to boisland]

Thanks boisland

Plus, big thanks to Dr Habib Ur Rehman, an internist in Canada, who noted that patients with Autonomic Dysfunction responded well to intramuscular vitamin B12.

The doctor has commented on long standing night sweats (hyperhydrosis). However, I know that night sweats can result in early morning waking, disturbed sleep, difficulties falling asleep, difficulties staying a sleep. So, the treatment is not zopliclone nor other benzodiazepines. It is vitamin B12 injections.

😉

[Technoid in reply to boisland]

for am111

extracted:

"This spectrum of disease usually presents in the absence of any changes in red blood cell indices and is easily misdiagnosed since serum levels of vitamin are in the “normal” range. Indeed, short-term fluctuations in HCy and MMA levels may also result in normal levels of these metabolites, thus obscuring the deficiency. This has been described previously in a patient who had total absence of vibratory sensation in the iliac crest, knees and ankles and normal levels of vitamin and metabolites, which resolved completely after 2 months of vitamin B12 therapy (8) . In this study, only 16% of patients with clinical response to cobalamin therapy had low serum levels of the vitamin and values were above 300pg/mL in 54% of cases. In addition, HCy and MMA values were in the normal range in 49% and 23% of cases respectively. Both metabolite levels were normal in 21% of cases. "

Anecdotally, I also had significant neurological damage which (mostly) recovered with treatment but 2 years after neurological symptoms started my B12 was 210, "low normal" and my MMA was not raised. A lot of doctors who gain a little knowledge of B12 , even if they realize that serum B12 is unreliable, think that MMA is foolproof and a gold standard diagnostic test. It is not.

[boisland in reply to Technoid]

Technoid - It is shameful that the majority of doctors do not pursue educating themselves on B12D. I do understand that MMA is not foolproof. Reading articles on B12D made that clear. One member in a FB group I belong to was adamant of such as she had a normal MMA however severely B12D. Thank you for your response, it is appreciated

[wedgewood in reply to Technoid]

Thanks for your reply .

I really despair when I read of the ignorance of GPs concerning B12 deficiency , and in particular P.A.. All sorts of sinister reasons for their attitude spring to mind, which I feel I should not voice .

So much scientific evidence is available , that there is no excuse for ignorance on the subject . as you so excellently demonstrate . Thank you Technoid .