| Proper name |
Cyanocobalamin |
| Category |
Vitamin |
| Functions |
Reduces RNA to DNA. Essential for cell division and repair. Needed for
the production of myelin, the sheath around all nerves. Deficiency can cause
peripheral neuropathy. Helps synthesize folate and the amino acid Methionine.
Needed for the maturation of red blood cells. Takes part in the metabolism
of protein, fats and carbohydrates. May help to prevent oral cancers in
smokers. Used by asthmatics to lessen symptoms. |
| RDA |
3-6 mcg per day for adults. |
| Therapeutic
dose |
30 mcg intramuscular up to daily in pernicious anemia, monthly for maintenance.
1,000 mcg per day orally. |
| Deficiency symptoms |
Pernicious anemia and megaloblastic anemia. Malabsorption syndrome (Sprue).
Peripheral neuropathy. Sore mouth and tongue. Amennorhea (lack of
menstruation). |
| Toxicity |
No known symptoms of toxicity even at doses 1,000 times the RDA. |
| Best
forms
|
Injectable. Best oral forms are adensylcobalamin and hydroxocobalamin |
| Food
sources |
Brewer's yeast, liver, lean meat, egg and cheese. |
| Lab
tests |
Shillings test, Serum B12 assay. |
| Drug
interactions |
B12 is depleted by Aminoglycosides, Cephalosporins, Chlorotrianisene, Chortetracycline,
Cholestyramine, Cimetidine, Cholchicine, Colestipol, Co-Trimoxazole, Demeclocycline,
Famotidine, Fluoroquinolones, Lansoprazole, Macrolides, Metformin, Minocycline,
Neomycin, Mizatidine, Omeprazole, Oral Contraceptives, Oxytetracycline,
Penicillins, Phentoin, Potassium Chloride, Ranitdine Bismuth Citrate, Ranitidine
Hydrochloride, Sulphamides, Tetracyclines, Trimethoprim, Zidovudine. Chronic
use of stomach medicines such as Axid, Pepcid, Tagamet, Zantac, Prevacid,
Prilosec can block the absorption of B12. |
| Nutrient interactions |
Works well with other nutrients. |
| Metabolism |
Cobalamin is split
from a protein complex by hydrochloric acid in the stomach then bound
to a glycoprotein called intrinsic factor (secreted by gastric mucosal
cells). It is then absorbed in the ileal portion of the small intestine.
It is then stored in the liver and other tissues for several years and
released slowly as needed.
|
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