I am adding your other post here since it is related and the forum rules prohibit opening a new thread for a continuing subject.
what alimentary cause causes poor absorption of high potency oral B12 supplements, necessitating IM injections of B12?
I should say first that it has been shown that people can absorb B12 taken orally if it is given in huge doses to compensate for the poor absorption so in answer to your question of high potency oral vitamins, studies have shown that 1,000 to 2.000 mcg would be needed daily to get the amount needed (equivalent to 2 mcg by injection). Keep in mind that absorption is variable with the individual which is why we have a broad range here.
The reason is related to intrinsic factors in the gut which are required for the absorption. Pernicious
anemia is one condition which causes B12 deficiency. There are many other conditions including long-term use of some medications that can result in such deficiency as well. Any process that interferes with gastric acid production can lead to this impairment. The acidic environment of the stomach facilitates the breakdown of vitamin B12 that is bound to food. The vitamin B12 intrinsic factor complex then
aids in the absorption of vitamin B12 in the terminal ileum.
Dietary sources of vitamin B12 are primarily meats and dairy products so vegetarians and vegans can be especially prone to a lack of B12. Alcoholics and the elderly are also at risk. But, the body does hold in reserve vitamin B12 so one can go several years without showing any signs of disease due to a lack in the vitamin through normal food intake.
I hope this helps. Best wishes to you.
The answers in online forums are for information only and are not intended to substitute for medical advice and care. Please see your personal health care provider for further evaluation of your individual case.
Debbie Miller, RN
