B12 must build up and be stored in quantities necessary for years of use. If not, the patient will decline terribly, either very slowly or rapidly.

It is not toxic, so there is no need to worry about it becoming a problem. What the body doesn't want to store or use it flushes out in the urine. B12 is used very slowly, but it can be built up pretty quickly.

Some other water soluable vitamins can build up. B6 for instance.

The doc almost surely is confusing megaloblastic anemia with "pernicious anemia." Megaloblastic anemia may not be present when one has "pernicious anemia," even in some cases in which the patient is being severely damaged by B12 deficiency. Until the intrinsic factor test, the doc hasn't begun to rule out pernicious anemia.

Pernicious anemia is not an anemia, and it is not an inability to use B12, it is an inability to absorb it normally.

When IF is not present (pernicious anemia), the patient must either have shots, take very large doses orally--1000 - 2000 mcg is the standard dose, or use some other method such as nasal (more difficult and expensive than oral).

Once the B12 is absorbed, it can be used just fine unless some other condition exists (that would be rare).

Pernicious is not rare. Malabsorption due to lack of sufficient stomach acid is far more common, and that sometimes progresses to the lack also of IF.

There is no worry about imbalance with B12 in relation to the other B vitamins. But, if you do not have one or more of the others in sufficient quantities, that can be a problem. And generally there should be a balance of the others, so a B complex is a good idea, in addition to the extra B12 at a different time of day.

Mercola has a lot of fabulous information, but he's not too hot on the B12. In fact, it looks like he didn't catch the fact that high MMA indicates either B12 deficiency or kidney problem, not low MMA as is suggested by the article.

Please remember that MMA does not increase in all cases of B12 deficiency, and when one takes B12 the MMA that is high can come down quickly so if it is tested after B12 has been taken it can be misleading.

They don't want to be responsible for you being on the cutting edge. The fact that they say eight a day shows that they are out front of most.

rose