What is it?
Vitamin B12 is a vitamin. It can be found in foods such as meat, fish, and dairy products. It can also be made in a laboratory.
Vitamin B12 is used for treating and preventing vitamin B12 deficiency, a condition in which vitamin B12 levels in the blood are too low. It is also used to treat pernicious anemia, a serious type of anemia that is due to vitamin B12 deficiency and is found mostly in older people. For this purpose, people use either a supplement that is taken by mouth or a gel that is applied inside the nose.
Vitamin B12 is also used for memory loss; Alzheimer’s disease; boosting mood, energy, concentration and the immune system; and slowing aging. It is also used for heart disease, lowering high homocysteine levels (which may contribute to heart disease), male infertility, diabetes, sleep disorders, depression, mental disorders, weak bones (osteoporosis), swollen tendons, AIDS, inflammatory bowel disease, asthma, allergies, a skin disease called vitiligo, preventing cervical and other cancers, and skin infections.
Some people use vitamin B12 for amyotrophic lateral sclerosis (Lou Gehrig’s disease), multiple sclerosis, preventing the eye disease age-related macular degeneration (AMD), Lyme disease and gum disease. It is also used for ringing in the ears, bleeding, liver and kidney disease, and for protection against the poisons and allergens in tobacco smoke.
Vitamin B12 is applied to the skin either alone or in combination with avocado oil for psoriasis and eczema.
Vitamin B12 is frequently used in combination with other B vitamins in various vitamin B complex products.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for VITAMIN B12 are as follows:
- Treatment and prevention of vitamin B12 deficiency, and diseases caused by low vitamin B12 levels.
- Treatment of pernicious anemia.
Likely effective for...
- Reducing a condition related to heart disease called “hyperhomocysteinemia” when taken with folic acid and vitamin B6.
Possibly effective for...
- Age-related macular degeneration (AMD). Some research shows that taking vitamin B12 with other vitamins including folic acid and vitamin B6 might help prevent getting the eye disease called age-related macular degeneration.
Possibly ineffective for...
- Sleep disorders.
- Preventing another stroke.
- Improving thinking and memory in people aged 65 and older, when used in combination with vitamin B6 and folic acid.
Insufficient evidence to rate effectiveness for...
- Shaky-leg syndrome. There are some reports that one form of vitamin B12 (cyanocobalamin) can help relieve tremor due to shaky-leg syndrome.
- Eczema (atopic dermatitis). Limited research shows that applying a specific vitamin B12 0.07% cream (Regividerm) to the affected area twice daily reduces the extent and severity of eczema.
- Alzheimer’s disease. Limited research suggests that higher vitamin B12 intake does not seem to prevent Alzheimer’s disease.
- Canker sores. Preliminary research shows that taking vitamin B12 1000 mcg under the tongue (sublingually) might help reduce the number of canker sore outbreaks, length of outbreaks, and pain caused by the canker sores.
- Cervical cancer. Increasing vitamin B12 intake from food and supplements, along with taking folic acid, thiamine, and riboflavin, might help to prevent cervical cancer.
- Breast cancer. There is no evidence that dietary vitamin B12 alone reduces the risk of breast cancer.
- Lung cancer. Preliminary evidence suggests that there is no relationship between levels of vitamin B12 in the blood and lung cancer.
- Chronic fatigue syndrome (CFS).
- Preventing re-blockage of blood vessels after heart artery dilation (balloon angioplasty).
- Fatigue or tiredness.
- Heart disease.
- Lyme disease.
- Immune system problems.
- Memory problems.
- Multiple sclerosis.
- High cholesterol.
- Other conditions.
More evidence is needed to rate vitamin B12 for these uses.
Vitamin B12 is required for the proper function and development of the brain, nerves, blood cells, and many other parts of the body.
Vitamin B12 is LIKELY SAFE for most people when taken by mouth or when the prescription-only, injectable product is used correctly. In some people, vitamin B12 might cause diarrhea, blood clots, itching, serious allergic reactions, and other side effects.
Vitamin B12 also appears to be safe when used on the skin for psoriasis. Mild itching has been reported in one person who used a specific avocado oil plus vitamin B12 cream for psoriasis.
Special precautions & warnings:
Pregnancy and breast-feeding: Vitamin B12 is LIKELY SAFE for pregnant or breast-feeding women when taken by mouth in the amounts recommended. The recommended amount for pregnant women is 2.6 mcg per day. Breast-feeding women should take no more than 2.8 mcg per day. Don’t take larger amounts. The safety of larger amounts is unknown.
High numbers of red blood cells (polycythemia vera): The treatment of vitamin B12 deficiency can unmask the symptoms of polycythemia vera.
Abnormal red blood cells (megaloblastic anemia): Megaloblastic anemia is sometimes corrected by treatment with vitamin B12. But this can have very serious side effects. Don’t attempt vitamin B12 therapy without close supervision by your healthcare provider.
Leber’s disease, a hereditary eye disease: Do not take vitamin B12 if you have this disease. It can seriously harm the optic nerve, which might lead to blindness.
Allergy or sensitivity to cobalt or cobalamin: Do not use vitamin B12 if you have this condition.
Do not take this combination.
Vitamin B12 is important for producing new blood cells. Chloramphenicol might decrease new blood cells. Taking chloramphenicol for a long time might decrease the effects of vitamin B12 on new blood cells. But most people only take chloramphenicol for a short time, so this interaction isn't a big problem.
Folic acid, particularly in large doses, can cover up vitamin B12 deficiency, and cause serious health effects. Be sure that your healthcare provider checks your vitamin B12 levels before you start taking folic acid.
Potassium supplements can reduce absorption of vitamin B12 in some people and might contribute to vitamin B12 deficiency.
Early research suggests that vitamin C supplements can destroy dietary vitamin B12. It isn't known whether this interaction is important, but to stay on the safe side, take vitamin C supplements at least 2 hours after meals.
Heavy drinking for at least a two-week period can decrease vitamin B12 absorption from the gastrointestinal tract.
The following doses have been studied in scientific research:
The typical general supplemental dose of vitamin B12 is 1-25 mcg per day.
The recommended dietary allowances (RDAs) of vitamin B12 are: Infants 0-6 months, 0.4 mcg; infants 7-12 months, 0.5 mcg; children 1-3 years, 0.9 mcg; children 4-8 years, 1.2 mcg; children 9-13 years, 1.8 mcg; older children and adults, 2.4 mcg; pregnant women, 2.6 mcg; and breast-feeding women, 2.8 mcg. Because 10% to 30% of older people do not absorb food-bound vitamin B12 efficiently, those over 50 years should meet the RDA by eating foods fortified with B12 or by taking a vitamin B12 supplement. Supplementation of 25-100 mcg per day has been used to maintain vitamin B12 levels in older people.
APPLIED TO THE SKIN:
- For vitamin B12 deficiency or pernicious anemia: cyanocobalamin doses of 300-10,000 mcg (microgram) daily have been used. However, some evidence suggests that the most effective oral dose is between 647-1032 mcg/day.
- For high blood levels of homocysteine: vitamin B12 500 mcg in combination with 0.5-5 mg folic acid and 16.5 mg pyridoxine has been used.
- For preventing age-related macular degeneration (AMD): vitamin B12 1 mg, folic acid 2.5 mg, and pyridoxine 50 mg daily has been studied.
- For atopic dermatitis (eczema): a specific vitamin B12 0.07% cream (Regividerm) applied twice daily has been used.
- For psoriasis: a specific cream (Regividerm, Regeneratio Pharma AG, Wuppertal, Germany) containing avocado oil plus vitamin B12 0.7 mg/gram applied for 12 weeks twice daily has been used.
B-12, B12, B Complex Vitamin, Bedumil, Cobalamin, Cobalamine, Cobamin, Cobamine, Complexe Vitaminique B, Cyanocobalamin, Cyanocobalamine, Cyanocobalaminum, Cycobemin, Hydroxocobalamin, Hydroxocobalamine, Hydroxocobalaminum, Hydroxocobemine, Hydroxocobémine, Idrossocobalamina, Methylcobalamin, Méthylcobalamine, Vitadurin, Vitadurine, Vitamina B12, Vitamine B12.
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.methodology (http://www.nlm.nih.gov/medlineplus/druginfo/natural/methodology.html).
To see all references for the Vitamin B12 page, please go to http://www.nlm.nih.gov/medlineplus/druginfo/natural/926.html.
- Lam JR, Schneider JL, Zhao W, et al. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA 2013;310:2435-42.
- Volkov I, Rudoy I, Freud T, et al. Effectiveness of vitamin B12 in treating recurrent aphthous stomatitis: a randomized, double-blind, placebo-controlled trial. J Am Board Fam Med 2009;22:9-16.
- Stucker M, Pieck C, Stoerb C, et al. Topical vitamin B12 - a new therapeutic approach in atopic dermatitis - evaluation of efficacy and tolerability in a randomized placebo-controlled multicentre clinical trial. Br J Dematol 2004;150:977-83.
- Luchsinger JA, Tang MX, Miller J, et al. Relation of higher folate intake to lower risk of Alzheimer disease in the elderly. Arch Neurol 2007;64:86-92.
- Ting RZ, Szeto CC, Chan MH, et al. Risk factors of vitamin B12 deficiency in patients receiving metformin. Arch Intern Med 2006;166:1975-9.
- Stucker M, Memmel U, Hoffmann M, et al. Vitamin B cream containing avocado oil in the therapy of plaque psoriasis. Dermatology 2001;203:141-7.
- Christen WG, Glynn RJ, Chew EY, et al. Folic acid, pyridoxine, and cyanocobalamin combination treatment and age-related macular degeneration in women. Arch Intern Med 2009;169:335-41.
- McMahon JA, Green TJ, Skeaff CM, Knight RG, Mann JI, Williams SM. A controlled trial of homocysteine lowering and cognitive performance. N Engl J Med 2006;354:2764-72.
- Van Guelpen B, Hultdin J, Johansson I, et al. Folate, vitamin B12, and risk of ischemic and hemorrhagic stroke: a prospective, nested case-referent study of plasma concentrations and dietary intake. Stroke 2005;36:1426-31.
- Bonaa KH, Njolstad I, Ueland PM, et al. NORVIT: Homocysteine lowering and cardiovascular events after acute myocardial infarction. N Enlg J Med 2006;354:1578-88.
Eussen SJ, de Groot LC, Clarke R, et al. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: A dose-finding trial. Arch Intern Med 2005;165:1167-72.
- Herrmann H. Prevention of cardiovascular events after percutaneous coronary intervention. N Engl J Med 2004;350:2708-10.
- Lange H, Suryapranata H, De Luca G, et al. Folate therapy and in-stent restenosis after coronary stenting. N Engl J Med 2004;350:2673-81.
- Hanley DF. The challenge of stroke prevention. JAMA 2004;291:621-2.
- Toole JF, Malinow MR, Chambless LE, et al. Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death: the Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial. JAMA 2004;291:565-75.
- Hernandez BY, McDuffie K, Wilkens LR, et al. Diet and premalignant lesions of the cervix: evidence of a protective role for folate, riboflavin, thiamin, and vitamin B12. Cancer Causes Control 2003;14:859-70.
- Jansen T, Romiti R, Kreuter A, Altmeyer P. Rosacea fulminans triggered by high-dose vitamins B6 and B12. J Eur Acad Dermatol Venereol 2001;15:484-5.
- Leonard JP, Desager JP, Beckers C, Harvengt C. In vitro binding of various biological substances by two hypocholesterolemic resins. Arzneimittelforschung 1979;29:97-81.
- Coronato A, Glass GB. Depression of the intestinal uptake of radio-vitamin B12 by cholestyramine. Proc Soc Exp Biol Med 1973;142:1341-4.
- Gharakhanian S, Navarette MS, Cardon B, Rozenbaum W. Vitamin B12 injections in patients treated with zidovudine. AIDS 1990;4:701-2.
- Falguera M, Perez-Mur J, Puig T, Cao G. Study of the role of vitamin B12 and folinic acid supplementation in preventing hematologic toxicity of zidovudine. Eur J Haematol 1995;55:97-102.
- Richman DD, Fischl MA, Grieco MH, et al. The toxicity of azidothymidine (AZT) in the treatment of patients with AIDS and AIDS-related complex. N Engl J Med 1987;317:192-7.
- Reynolds EH. Schizophrenia-like psychoses of epilepsy and disturbances of folate and vitamin B12 metabolism induced by anticonvulsant drugs. Br J Psychiatry 1967;113:911-9.
- Frenkel EP, McCall MS, Sheehan RG. Cerebrospinal fluid folate and vitamin B12 in anticonvulsant-induced megaloblastosis. J Lab Clin Med 1973;81:105-15.
- Reynolds EH, Hallpike JF, Phillips BM, et al. Reversible absorptive defects in anticonvulsant megaloblastic anemia. J Clin Pathol 1965;18:593-8.
- Lees F. Radioactive vitamin B12 absorption in the megaloblastic anemia caused by anticonvulsant drugs. Q J Med 1961;30:231-48.
- Palva IP, Salokannel SJ, Palva HLA, et al. Drug-induced malabsorption of vitamin B12. VII Malabsorption of B12 during treatment with potassium citrate. Acta Med Scand 1974;196:525-6.
- Ellis FR, Nasser S. A pilot study of vitamin B12 in the treatment of tiredness. Br J Nutr 1973;30:277-83.
- Seal EC, Metz J, Flicker L, Melny J. A randomized, double-blind, placebo-controlled study of oral vitamin B12 supplementation in older patients with subnormal or borderline serum vitamin B12 concentrations. J Am Geriatr Soc 2002;50:146-51.
- Louwman MW, van Dusseldorp M, van de Vijver FJ, et al. Signs of impaired cognitive function in adolescents with marginal cobalamin status. Am J Clin Nutr 2000;72:762-9.
- Russell RM, Baik H, Kehayias JJ. Older men and women efficiently absorb vitamin B-12 from milk and fortified bread. J Nutr 2001;131:291-3.
- Gardyn J, Mittelman M, Zlotnik J, et al. Oral contraceptives can cause falsely low vitamin B12 levels. Acta Haematol 2000;104:22-4.
- Package insert for Paser granules. Jacobus Pharmaceutical Co., Inc. Princeton, NJ. July 1996.
- Kinsella LJ, Green R. Anesthesia paresthetica: nitrous oxide-induced cobalamin deficiency. Neurology 1995;45:1608-10.
- Force RW, Meeker AD, Cady PS, et al. Increased vitamin B12 requirement associated with chronic acid suppression therapy. Ann Pharmacother 2003;37:490-3.
- Marie RM, Le Biez E, Busson P, et al. Nitrous-oxide anesthesia-associated myelopathy. Arch Neurol 2000;57:380-2.
- Bauman WA, Spungen AM, Shaw S, et al. Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. Diabetes Care 2000;23:1227-31.
- Andres E, Noel E, Goichot B. Metformin-associated vitamin B12 deficiency (letter). Arch Intern Med 2002;162:2251-2.
- Gilligan MA. Metformin and vitamin B12 deficiency (letter). Arch Intern Med 2002;162:484-5.
- Callaghan TS, Hadden DR, Tomkin GH. Megaloblastic anemia due to vitamin B12 malabsorption associated with longterm metformin treatment. Br Med J 1980;280:1214-5.
- Fishman SM, Christian P, West KP. The role of vitamins in the prevention and control of anaemia. Public Health Nutr 2000;3:125-50.
- Force RW, Nahata MC. Effect of histamine H2 receptor antagonists on vitamin B12 absorption. Ann Pharmacother 1992;26:1283-6.
- Ruscin JM, Page RL, Valuck RJ. Vitamin B12 deficiency associated with histamine-2-receptor antagonists and a proton-pump inhibitor. Ann Pharmacother 2002;36:812-6.
- Mezzano D, Kosiel K, Martinez C, et al. Cardiovascular risk factors in vegetarians: normalization of hyperhomocysteinemia with vitamin B12 and reduction of platelet aggregation with n-3 fatty acids. Thromb Res 2000;100:153-60.
- Herbert V, Jacob E. Destruction of vitamin B12 by ascorbic acid. JAMA 1974;230:241-2.
- Tyrer LB. Nutrition and the pill. J Reprod Med 1984;29:547-50.
- Goldin BR, Lichtenstein AH, Gorbach SL. Nutritional and metabolic roles of intestinal flora. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th ed. Malvern, PA: Lea & Febiger, 1994.
- Badner NH, Freeman D, Spence JD. Preoperative oral B vitamins prevent nitrous oxide-induced postoperative plasma homocysteine increases. Anesth Analg 2001;93:1507-10.
- Hartman TJ, Woodson K, Stolzenberg-Solomon R, et al. Association of the B-vitamins pyridoxal 5'-phosphate (B6), B12, and folate with lung cancer risk in older men. Am J Epidemiol 2001;153:688-94.
- Bostom AG, Shemin D, Gohh RY, et al. Treatment of hyperhomocysteinemia in hemodialysis patients and renal transplant recipients. Kidney Int 2001;59:s246-s252.
- Dierkes J, Domrose U, Bosselmann P, et al. Homocysteine lowering effect of different multivitamin preparations in patients with end-stage renal disease. J Renal Nutr 2001;11:67-72.
- Bostom A, Shemin D, Gohh R, et al. Treatment of mild hyperhomocysteinemia in renal transplant recipients versus hemodialysis patients. Transplantation 2000;69:2128-31.
- Schnyder G, Roffi M, Flammer Y, et al. Effect of homocysteine-lowering therapy with folic acid, vitamin B12, and vitamin B6 on clinical outcome after percutaneous coronary intervention. The Swiss Heart Study: A randomized controlled trial. JAMA 2002;288:973-9.
- Boushey CJ, Beresford SA, 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;274:1049-57.
- den Heijer M, Brouwer IA, Bos GMJ, et al. Vitamin supplementation reduces blood homocysteine levels. A controlled trial in patients with venous thrombosis and healthy volunteers. Arterioscler Thromb Vasc Biol 1998;18:356-61.
- Sunder-Plassmann G, Winkelmayer WC, Fodinger M. Therapeutic potential of total homocysteine-lowering drugs on cardiovascular disease. Expert Opin Investig Drugs 2000;9:2637-51.
- Keebler ME, De Souza C, Fonesca V. Diagnosis and treatment of hyperhomocysteinemia. Curr Atheroscler Rep 2001;3:54-63.
- Selhub J, Jacques PF, Bostom AG, et al. Relationship between plasma homocysteine and vitamin status in the Framingham study population. Impact of folic acid fortification. Publ Health Rev 2000;28:117-45.
- Clarke R, Armitage J. Vitamin supplements and cardiovascular risk: review of the randomized trials of homocysteine-lowering vitamin supplements. Semin Thromb Hemost 2000;26:341-8.
- Holven KB, Holm T, Aukrust P, et al. Effect of folic acid treatment on endothelium-dependent vasodilation and nitric oxide-derived end products in hyperhomocysteinemic subjects. Am J Med 2001;110:536-42.
- Ueland PM, Refsum H, Beresford SA, Vollset SE. The controversy over homocysteine and cardiovascular risk. Am J Clin Nutr 2000;72:324-32.
- Bronstrup A, Hages M, Prinz-Langenohl R, Pietrzik K. Effects of folic acid and combinations of folic acid and vitamin B12 on plasma homocysteine concentrations in healthy young women. Am J Clin Nutr 1998;68:1104-10.
- Homocysteine Lowering Trialists' Collaboration. Lowering blood homocysteine with folic acid based supplements: meta-analysis of randomized trials. BMJ 1998;316:894-8.
- Halsted CH, McIntyre PA. Intestinal malabsorption caused by aminosalicylic acid therapy. Arch Int Med 1972;130;935-9.
- Line DH, Seitanidis B, Morgan JO, Hoffbrand AV. The effects of chemotherapy on iron, folate, and vitamin B12 metabolism in tuberculosis. Q J Med 1971;40:331-40.
- Mooij PN, Thomas CM, Doesburg WH, Eskes TK. Multivitamin supplementation in oral contraceptive users. Contraception 1991;44:277-88.
- Barone C, Bartoloni C, Ghirlanda G, Gentiloni N. Megaloblastic anemia due to folic acid deficiency after oral contraceptives. Haematologica 1979;64:190-5.
- Shojania AM. Oral contraceptives: effect on folate and vitamin B12 metabolism. Can Med Assoc J 1982;126:244-7.
- Garcia A, Paris-Pombo A, Evans L, et al. Is low-dose oral cobalamin enough to normalize cobalamin function in older people? J Am Geriatr Soc 2002;50:1401-4.
- Smith AD. Homocysteine, B vitamins, and cognitive deficit in the elderly. Am J Clin Nutr 2002;75:785-6.
- Duthie SJ, Whalley LJ, Collins AR, et al. Homocysteine, B vitamin status, and cognitive function in the elderly. Am J Clin Nutr 2002;75:908-13.
- Shrubsole MJ, Jin F, Dai Q, et al. Dietary folate intake and breast cancer risk: results from the Shanghai Breast Cancer Study. Cancer Res 2001;61:7136-41.
- van der Dijs FP, Fokkema MR, Dijck-Brouwer DA, et al. Optimization of folic acid, vitamin B12, and vitamin B6 supplements in pediatric patients with sickle cell disease. Am J Hematol 2002;69:239-46.
- Stehouwer CD. Clinical relevance of hyperhomocysteinaemia in atherothrombotic disease. Drugs and Aging 2000;16:251-60.
- Nallamothu BK, Fendrick M, Rubenfire M, et al. Potential clinical and economic effects of homocyst(e)ine lowering. Arch Intern Med 2000;160:3406-12.
- Bauman WA, Shaw S, Jayatilleke E, et al. Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. Diabetes Care 2000;23:1227-31.
- Deutch B, Jorgensen EB, Hansen JC. n-3 PUFA from fish or seal oil reduce atherogenic risk indicators in Danish women. Nutr Res 2000;20:1065-77.
- Jacobson ED, Faloon WW. Malabsorptive effects of neomycin in commonly used doses. JAMA 1961;175:187-90.
- Schnyder G, Roffi M, Pin R, et al. Decreased rate of coronary stenosis after lowering of plasma homocysteine levels. N Engl J Med 2001;345:1593-600.
- Schnyder G, Roffi M, Pin R, et al. Decreased rate of coronary restenosis after lowering of plasma homocysteine levels. N Engl J Med 2001;345:1593-600.
- Beaulieu AJ, Gohh RY, Han H, et al. Enhanced reduction of fasting total homocysteine levels with supraphysiological versus standard multivitamin dose folic acid supplementation in renal transplant recipients. Arterioscler Thromb Vasc Biol 1999;19:2918-21.
- Grace E, Emans SJ, Drum DE. Hematologic abnormalities in adolescents who take oral contraceptive pills. J Pediatrics 1982;101:771-4.
- Shen CL, Song W, Pence BC. Interactions of selenium compounds with other antioxidants in DNA damage and apoptosis in human normal keratinocytes. Cancer Epidemiol Biomarkers Prev 2001;10:385-90.
- Zapletal C, Heyne S, Golling M, et al. Influence of selenium therapy on liver microcirculation after warm ischemia/reperfusion: an intravital microscopy study. Transplant Proc 2001;33:974-5.
- Manns B, Hyndman E, Burgess E, et al. Oral vitamin B and high-dose folic acid in hemodialysis patients with hyper-homocyst(e)inemia. Kidney Int 2001;59:1103-9.
- Anon. Petasites hybridus. Altern Med Rev 2001;6:207-9.
- Tremblay R, Bonnardeaux A, Geadah D, et al. Hyperhomocystinemia in hemodialysis patients: effects of 12-month supplementation with hydrosoluble vitamins. Kidney Int 2000;58:851-8.
- Booth GL, Wang EE. Preventive health care, 2000 update: screening and management of hyperhomocysteinemia for the prevention of coronary artery disease events. The Canadian Task Force on Preventive Health Care. CMAJ 2000;163:21-9.
- Benito-Leon J, Porta-Etessam J. Shaky-leg syndrome and vitamin B12 deficiency. N Engl J Med 2000;342:981.
- Penninx BW, Guralnik JM, Ferrucci L, et al. Vitamin B deficiency and depression in physically disabled older women: epidemiologic evidence from the Women's Health and Aging Study. Am J Psychiatry 2000;157:715-21.
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline . Washington, DC: National Academy Press, 2000. Available at: http://books.nap.edu/books/0309065542/html/.
- Werbach MR. Nutritional strategies for treating chronic fatigue syndrome. Altern Med Rev 2000;5:93-108.
- Ehrenfeld M, Levy M, Sharon P, et al. Gastrointestinal effects of long-term colchicine therapy in patients with recurrent polyserositis (Familial Mediterranean Fever). Dig Dis Sci 1982;27:723-7.
- Clarke R. Prevention of vitamin B-12 deficiency in old age. Am J Clin Nutr. 2001;73:151-152.
- Toskes PP, Deren JJ. Selective inhibition of vitamin B12 absorption by para-aminosalicylic acid. Gastroenterology 1972;62:1232-7.
- Hielt K, Brynskov J, Hippe E, et al. Oral contraceptives and the cobalamin (vitamin B12) metabolism. Acta Obstet Gynecol Scand 1985;64:59-63.
- Webb DI, Chodos RB, Mahar CQ, et al. Mechanism of vitamin B12 malabsorption in patients receiving colchicine. N Engl J Med 1968;279:845-50.
- Faloon WW, Chodos RB. Vitamin B12 absorption studies using cochicines, neomycin and continuous 57Co B12 administration. Gastroenterology 1969;56:1251.
- Race TF, Paes IC, Faloon WW. Intestinal malabsorption induced by oral colchicine. Comparison with neomycin and cathartic agents. Am J Med Sci 1970;259:32-41.
- Salom IL, Silvis SE, Doscherholmen A. Effect of cimetidine on the absorption of vitamin B12. Scand J Gastroenterol 1982;17:129-31.
- Belaiche J, Zittoun J, Marquet J, et al. Effect of ranitidine on secretion of gastric intrinsic factor and absorption of vitamin B12. Gastroenterol Clin Biol 1983;7:381-4.
- Aymard JP, Aymard B, Netter P, et al. Haematological adverse effects of histamine H2-receptor antagonists. Med Toxicol Adverse Drug Exp 1988;3:430-48.
- Salokannel SJ, Palva IP, Takkunen JT, et al. Malabsorption of vitamin B12 during treatment with slow-release potassium chloride. Preliminary report. Acta Med Scand 1970;187:431-2.
- Palva IP, Salokannel SJ, Timonen T, et al. Drug-induced malabsorption of vitamin B12. IV. Malabsorption and deficiency of B12 during treatment with slow-release potassium chloride. Acta Med Scand 1972;191:355-7.
- Prasad AS, Lei KY, Moghissi KS, et al. Effect of oral contraceptives on nutrients. III. Vitamins B6, B12 and folic acid. Am J Obstet Gynecol 1976;125:1063-9.
- Carpentier JL, Bury J, Luyckx A, et al. Vitamin B12 and folic acid serum levels in diabetics under various therapeutic regimens. Diabete Metab 1976;2:187-90.
- Marcuard SP, Albernaz L, Khazaine PG. Omeprazole therapy causes malabsorption of cyanocobalamin. Ann Intern Med 1994;120:211-5.
- Saltzman JR, Kemp JA, Golner BB, et al. Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption. J Am Coll Nutr 1994;13:584-91.
- Bellou A, Aimone-Gastin I, De Korwin JD, et al. Cobalamin deficiency with megaloblastic anaemia in one patient under long-term omeprazole therapy. J Intern Med 1996;240:161-4.
- Termanini B, Gibril F, Sutliff VE, et al. Effect of long-term gastric acid suppressive therapy on serum vitamin B12 levels in patients with Zollinger-Ellison syndrome. Am J Med 1998;104:422-30.
- West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8.
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5.
- Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
- Voutilainen S, Lakka TA, Porkkala-Sarataho E, et al. Low serum folate concentrations are associated with an excess incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study. Eur J Clin Nutr 2000;54:424-8.
- Lindenbaum J, Healton EB, Savage DG, et al. Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis. N Engl J Med 1988;318:1720-8.
- Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: The new basis for recommendations for calcium and related nutrients, B vitamins, and choline. J Am Diet Assoc 1998;98:699-706.
- Fauci AS, Braunwald E, Isselbacher KJ, et al. Harrison's Principles of Internal Medicine, 14th ed. New York, NY: McGraw-Hill, 1998.
- Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.
- Mayer EL, Jacobsen DW, Robinson K. Homocysteine and coronary atherosclerosis. J Am Coll Cardiol 1996;27:517-27.
- Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
- Hathcock JN, Troendle GJ. Oral cobalamin for treatment of pernicious anemia? JAMA 1991;265:96-97.
- Kastrup EK. Drug Facts and Comparisons. 1998 ed. St. Louis, MO: Facts and Comparisons, 1998.
- Lindenbaum J, Rosenberg IH, Wilson PW, et al. Prevalence of cobalamin deficiency in the Framingham elderly population. Am J Clin Nutr 1994;60:2-11.
- Allen LH, Casterline J. Vitamin B-12 deficiency in elderly individuals: diagnosis and requirements. Am J Clin Nutr 1994;60:12-14.
- Verhaeverbeke I, Mets T, Mulkens K, Vandewoude M. Normalization of low vitamin B12 serum levels in older people by oral treatment. J Am Geriatr Soc 1997;45:124-5.
- Andres E, Goichot B, Schlienger JL. Food cobalamin malabsorption: a usual cause of vitamin B12 deficiency. Arch Intern Med 2000;160:2061-2.
- Elia M. Oral or parenteral therapy for B12 deficiency. Lancet 1998;352:1721-2.
- Lederle FA. Oral cobalamin for pernicious anemia. Medicine's best kept secret? JAMA 1991;265:94-5
- Andres E, Kurtz JE, Perrin AE, et al. Oral cobalamin therapy for the treatment of patients with food-cobalamin malabsorption. Am J Med 2001;111:126-9.
- Kuzminski AM, Del Giacco EJ, et al. Effective treatment of cobalamin deficiency with oral cobalamin. Blood 1998;92:1191-1198.
- Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
- Brattstrom LE, Israelsson B, Jeppsson JO, et al. Folic acid-an innocuous means to reduce plasma homocysteine. Scand J Clin Lab Invest 1988;48:215-21.
- Landgren F, Israelsson B, Lindgren A, et al. Plasma homocysteine in acute myocardial infarction: homocysteine-lowering effect of folic acid. J Intern Med 1995;237:381-8.
- Christensen B, Landaas S, Stensvold I, et al. Whole blood folate, homocysteine in serum, and risk of first acute myocardial infarction. Atherosclerosis 1999;147:317-26.
- Bostom AG, Gohh RY, Beaulieu AJ, et al. Treatment of hyperhomocysteinemia in renal transplant recipients. A randomized, placebo-controlled trial. Ann Intern Med 1997;127:1089-92.
- Stabler SP, Allen RH, Fried LP, et al. Racial differences in prevalence of cobalamin and folate deficiencies in disabled elderly women. Am J Clin Nutr 1999;70:911-9.
- Carmel R, Green R, Jacobsen DW, et al. Serum cobalamin, homocysteine, and methylmalonic acid concentrations in a multiethnic elderly population: ethnic and sex differences in cobalamin and metabolite abnormalities. Am J Clin Nutr 1999;70:904-10.
- Houston DK, Johnson MA, Nozza RJ, et al. Age-related hearing loss, vitamin B-12, and folate in elderly women. Am J Clin Nutr 1999;69:564-71.
- Mayer G, Kroger M, Meier-Ewert K. Effects of vitamin B12 on performance and circadian rhythm in normal subjects. Neuropsychopharmacology 1996;15:456-64.
- Ohta T, Ando K, Iwata T, et al. Treatment of persistent sleep-wake schedule disorders in adolescents with methylcobalamin (vitamin B12). Sleep 1991;14:414-8.
- Yamadera H, Takahashi K, Okawa M. A multicenter study of sleep-wake rhythm disorders: therapeutic effects of vitamin B12, bright light therapy, chronotherapy and hypnotics. Psychiatry Clin Neurosci 1996;50:203-9.
- Okawa M, Takahashi K, Egashira K, et al. Vitamin B12 treatment for delayed sleep phase syndrome: a multi-center double-blind study. Psychiatry Clin Neurosci 1997;51:275-9.
- Okawa M, Uchiyama M, Ozaki S, et al. Circadian rhythm sleep disorders in adolescents: clinical trials of combined treatments based on chronobiology. Psychiatry Clin Neurosci 1998;52:483-90.
- Yamadera W, Sasaki M, Itoh H, et al. Clinical features of circadian rhythm sleep disorders in outpatients. Psychiatry Clin Neurosci 1998;52:311-6.
- Carlsen SM, Folling I, Grill V, et al. Metformin increases total homocysteine levels in non-diabetic male patients with coronary heart disease. Scand J Clin Lab Invest 1997;57:521-7.
- Paltiel O, Falutz J, Veilleux M, et al. Clinical correlates of subnormal vitamin B12 levels in patients infected with the human immunodeficiency virus. Am J Hematol 1995;49:318-22.
- McKevoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- Show more references
- Show fewer references
Last reviewed - 01/29/2014
This copyrighted, evidence-based medicine resource is provided by Natural Medicines Comprehensive Database Consumer Version. Natural Medicines Comprehensive Database disclaims any responsibility related to consequences of using any product. This monograph should not replace advice from a healthcare professional and should not be used for the diagnosis or treatment of any medical condition.
Copyright © 1995 - 2013 Therapeutic Research Faculty
, publishers of Natural Medicines Comprehensive Database
, Prescriber’s Letter
, Pharmacist’s Letter
. All rights reserved. For scientific data on natural medicines, professionals may consult the Professional Version of Natural Medicines Comprehensive DatabaseNatural Medicines Comprehensive Database (http://www.naturaldatabase.com/)