Vitamin B-12 Cyanocobalamin 500 mcg

Vitamin B-12 Cyanocobalamin 500 mcg

Description

Vitamin B-12 tablets dissolve rapidly, releasing 500 mcg of pure vitamin B-12

Functions

Vitamin B-12 is essential for normal energy metabolism of carbohydrates, fat and protein. As a cofactor for methylmalonyl-CoA mutase enzymes, vitamin B-12 helps convert odd chain fatty acids and branched chain amino acids into succinyl-CoA, a common citric acid cycle intermediate. Vitamin B-12 is also required for nucleic acid (DNA) synthesis, methionine synthesis from cysteine and normal myelin synthesis in the nervous system. Along with vitamin B-6 and folic acid, adequate levels of vitamin B-12 are required to maintain normal plasma homocysteine levels. Elevated plasma homocysteine may be an independent risk factor for developing cardiovascular disease. There are two distinct mechanisms for intestinal vitamin B-12 absorption: receptor-mediated absorption and passive diffusion. In the first, vitamin B-12 attaches to a salivary "R-binder" protein which transports it into the small intestine, where vitamin B-12 is released. The vitamin then binds to "Intrinsic Factor" (IF), a glycoprotein normally produced by the gastric parietal cells. This vitamin B-12-IF complex is carried down to the ileum, where it binds to mucosal receptors. Finally, the complex is absorbed and bound to serum vitamin B-12-binding proteins. The second absorption mechanism, passive diffusion, does not require any carriers, such as B-binder or IF. Only about 1% of free vitamin B-12 is passively absorbed, but this can be nutritionally significant with higher dietary vitamin B-12 intakes. The elderly, HIV/AIDS patients and strict vegetarians are often at risk for vitamin B-12 deficiency, either due to low dietary intake or impaired absorption. The receptor-mediated absorption pathway is subject to numerous genetic and pathologic defects which can severely impair normal vitamin B-12 absorption. These defects include hereditary absence of IF production, gastric atrophy, gastrectomy and small intestinal disorders affecting the ileum, such as gluten-induced enteropathy, regional enteritis, chronic diarrhea and intestinal resection. Affected individuals depend almost exclusively on the passive diffusion pathway, which requires high dietary vitamin B-12 intakes

Indications

Vitamin B-12 tablets may be a useful nutritional adjunct for individuals who wish to increase their intake of vitamin B-12

Supplement Facts

Suggested Use

As a dietary supplement, adults take 1 tablet daily with meals, or as directed by a healthcare professional

Side Effects

No adverse effects have been reported

Storage

Store in a cool, dry place, away from direct light. Keep out of reach of children

References

1. Boushey CJ, Beresford SAA, Omenn GS, Motulsky AG. A quantitative assessment of plasma homocysteine as a risk factor for vascular disease - Probable benefits of increasing folic acid intakes. JAMA 1995;274:1049-1057
2. Curtis D, Sparrow R, Brennan L, Van Der Weyden MB. Elevated serum homocysteine as a predictor for vitamin B12 or folate deficiency. Eur J Haematol 1994;52:227-232
3. Ehrenpreis ED, Carlson SJ, Boorstein HL, Craig RM. Malabsorption and deficiency of vitamin B12 in HIV-infected patients with chronic diarrhea. Dig Dis Sci 1994;39:2159- 2162
4. Flynn MA, Irvin W, Krause G. The effect of folate and cobalamin on osteoarthritic hands. J Am Coll Nutr 1994;13:351-356
5. Harriman GR, Smith PD, Horne MK, et al. Vitamin B12 malabsorption in patients with acquired immunodeficiency syndrome. Arch Intern Med 1989;149:2039-2041
6. Herzlich BC, Schiano TD. Reversal of apparent AIDS dementia complex following treatment with vitamin B12. J Intern Med 1993;233:495-497
7. Herzlich BC, Schiano TD, Moussa Z, et al. Decreased intrinsic factor secretion in AIDS: relation to parietal cell acid secretory capacity and vitamin B12 malabsorption. Am J Gastroenterol 1992;87:1781-1788
8. Rauma AL, Törrönen R, Hänninen O, Mykkänen H. Vitamin B-12 status of long-term adherents of a strict uncooked vegan diet ("living food diet") is compromised. J Nutr 1995;125:2511-2515
9. Saltzman JR, Kemp JA, Golner BB, Pedrosa MC, Dallal GE, Russell RM. Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption. J Am Coll Nutr 1994;13:584-591. Vitamin B-12 Cyanocobolamin 500 mcg

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.