Vitamin B12 absorbtion

[sophie]

I'm just wondering if anyone knows about B12 absorbtion, specifically if people absorb it at different rates. the reason I'm wondering is that my younger sister, who is vegan, has just had blood tests and is low in B12, This is despite the fact she takes a regular B12 supplement. She has been taking the supplement since she got very low in B12 over a year ago, and her symptoms had since disappeared so she thought she was ok. She got the blood tests done because she couldn't shake off a persistent cold, and was feeling generally sluggish. Her iron and everything was fine, it was just the B12. the thing is, I take exactly the same B12 supplement, and my B12 levels are fine (I had a test recently when pregnant). So I was wondering if anyone knows the reasons why one person could absorb it differently from another, eg dietary factors (like vitamin c helping iron absorbtion etc.) Also, has anyone ever had a B12 injection, as this is what the doctor is reccommending for my sister.
Thanks!

[Christa]

I certainly do not know everything about this, but here are a few thoughts.

Things that can reduce B-12 absorption:

1) exposure to cigarette smoke (cyanide content of cig. smoke is detoxified in such a manner that it depletes stores of B-12).
2) GI problems in general (malabsorption in the intestines) can interfere w/ absorption of many vitamins.
3) Nicotine, alcohol, and caffeine can destroy B-12.
4) Excessive blood levels of protein, vitamin C and calcium.
5) Oral contaceptives.
6) Intestinal parasites.
7) Very elderly people can have difficulty absorbing B-12.
8) chronic infection, liver disease, tb, cancer, or prior surgery of the stomach or bowels.
9) low thyroid function.
10) poor pancreas functioning.

Many of these may not be relevant to your sister, but she may want to make sure that she is not taking high levels of vitamin C, such as those used as a home remedy to ward off colds. She should also avoid high doses of vitamin B-1, as it too can destroy B-12. Excessive intake of soy protein, especially uncooked soybeans, can also increase excretion of B-12 in some people. I have also seen suggestions that you chew food very thoroughly, and not eat a large variety of foods at one meal to increase B-12 absorption.

Also, low serum levels of B-12, depending on the levels, may not indicate a true problem. Unless she is exhibiting signs of pernicious anemia, she may want to consider waiting and seeing before being treated for pernicious anemia. Some studies have shown that tall, blue-eyed people, those with premature graying of hair, those of northern-European ancestry, and males are more likely to suffer from pernicious anemia.

Sorry that this is so long - I hope that something here helps!

[sophie]

Thanks a lot Christa, that info is really interesting and I'll pass it on to my sister.