agreed - cofactors are key. zinc's a big one known boost B12 absorption, and zinc can be a trouble spot for folks who don't eat meat, and also for ms patients.
re the b12 normal range again, agree. it's baloney developed for hematological criteria only. the lower cutoff has to do with the point at which your red blood cells start to get larger. as if keeping your blood cells a particular size is the only thing b12 has to do in your body 7:S
there's an old article out there somewhere that supports the 500 pg/mL minimum for b12. I ordered it once because it was impossible to find online even with full text access. for a pmol/L target multiply by 0.738.
celeste re the docs telling you normal, these excerpts are taken from the link I sent you above:
"note that ms patients and healthy controls can typically all be described as 'normal'. the difference between patients and 'healthies' is RELATIVE deficiency, generally found within the normal range, eg low normal vs high normal."
"The first thing to understand when beginning nutrition investigations, is the unfortunate language of the lab. Specifically, the term 'normal'.
As described briefly above, the 'normal' range is often quite a broad range which in many cases includes both sick and healthy people.
There is a much smaller range within the normal range that can be described as 'optimal'."
"One example of the danger of the word 'normal' is this: recently a patient here at TIMS asked for a zinc test and was told the level was fine. When the patient asked for the number it came back 10.083 umol/L (normal range 10-20 in this case). This patient was not told that the level was suboptimal, borderline deficient, or outright deficient (which it was, if you use 11.5 - the WHO's lower cutoff level..) just that it was 'fine' - ie the computer did not red flag it because the value was within that lab's min and max setpoints."
more of this at regimens-f22/topic2489.html#p15460