As was presented earlier, the daily requirement of the body for this essential vitamin is very small (less than 1 mcg. [microgram], 1 millionth of a gram). The liver normally has a store of vitamin B12 which will meet the bodies needs for this vitamin for 3 to 6 years.
Typical B12 supplements contain 1,000 to 3,000 mcg. per tablet. 1,000 mcg of B12 in the liver would be about a 3 year supply of the vitamin. Many people are taking great amounts of B12 and not seeing much lasting benefit to the daily supplementation. (Note: There is no cause for concern in overdosing or developing an accumulated toxicity by taking large doses of vitamin B12.) The point I want to make is that if the body needs so little on a daily basis and a person is taking much more than is required and still not benefiting, maybe the body is not absorbing it. Or, if it is, it may not be in the right form for the body to use.
As we know, vitamin B12 is found in meat. When we eat the steak, which is largely protein, the stomach acid must reach a very low pH in order to activate the enzymes necessary to break down protein. The same cells that release the elements which combine to produce stomach acid also release a substance called Intrinsic Factor (IF). Intrinsic Factor must bind with vitamin B12 in the stomach if the vitamin is to be absorbed.
The mechanism for vitamin B12 absorption into the body is located in the small intestine, near the end of the small intestine, an inch or two from where it joins the large intestine (colon).
When the liquified food from the stomach, called chyme, reaches the point toward the end of the small intestine vitamin B12 is absorbed into the body. The mechanism for vitamin B12 absorption requires that Intrinsic Factor is binded to the B12 in order for it to be absorbed. Absorption of B12 at this point only happens if Intrinsic Factor has already binded with the B12 in the stomach. If there is no Intrinsic Factor binding to the B12, the B12 passes through the colon and out the body. This is what I suspect is happening to the majority of vitamin B12 supplements people take.
If you noticed on the page "Drugs that deplete vitamins", all the antacid type medications show a vitamin B12 depleting effect. This is possibly because antacids neutralize stomach acid, raising the stomach pH out of the pH range needed for the release of Intrinsic Factor. Remember, no intrinsic factor, no vitamin B12 absorption.
Just as bacteria in the cows digestive system work to synthesis vitamins, within the human digestive system there is also a large number of bacteria at work helping the body synthesize and absorb different nutrients. If there is an imbalance in these "friendly" bacteria in the human digestive system it could potentially impact the ability of the body to absorb certain nutrients.
On the next page we will look at some of the possible ways that the balance of intestinal bacteria (intestinal flora) could be upset.
Speculation:
If you look at the picture in the
lower left of the page you see that near the area where B12 is absorbed
into the body are many blood vessels that lead to the liver. Question:
If there is one specific point that B12 is absorbed into the body, is
it possible that other systems in the body that need B12 are designed
to receive it from a specific location? Maybe the systems in the body
that need B12 have their trucks lined up at the loading docks in the
liver awaiting the arrival of B12. Hence, the possible reason for short
term relief from B12 injections into the muscle. Anyway, something to
think about.
Related Links |
| Lets get on Tract!; Chapter 24, Digestive System |
| The Digestive System |
| Hypochlorhydria |