Causes of High Blood Levels of Vitamin B12
Vitamin B12, or cobalamin, is important for the development of healthy red blood cells and proper nervous system function. The main dietary sources of vitamin B12 include meat, dairy and fish. While doctors are often more concerned with low vitamin B12 levels, high levels might also signal a serious medical problem. Elevated blood levels of vitamin B12 are generally associated with increased amounts of proteins that carry vitamin B12 in the bloodstream or release of stored vitamin B12.
Excess Vitamin Supplements
The most obvious cause of an elevated vitamin B12 level is taking too much of the vitamin in the form of supplements. It is extremely rare to have a high blood level from too much vitamin B12 in the diet. While vitamin B12 is generally not considered toxic in high levels, it's important to determine if the elevation is due to excess vitamin supplements since other causes of a high vitamin B12 level are usually serious.
Leukemia and Related Blood Diseases
Causes of Elevated B-12 Levels
High vitamin B12 levels are associated with many blood diseases, including various types of leukemia and related blood disorders. According to a September 2012 study in "PLoS One," people with high vitamin B12 had a 4- to 18-times higher risk of having a blood disease. Chronic myeloid leukemia is one such disease, in which the elevated vitamin B12 levels are thought to be due to release of excess B12 carrier proteins from the cancerous white blood cells. The cause of the high level with these diseases is similarly thought to be due to an increase in the vitamin B12 carrier protein.
- High vitamin B12 levels are associated with many blood diseases, including various types of leukemia and related blood disorders.
- Chronic myeloid leukemia is one such disease, in which the elevated vitamin B12 levels are thought to be due to release of excess B12 carrier proteins from the cancerous white blood cells.
Solid Organ Cancers
An elevated vitamin B12 level can be a nonspecific indicator of several types of solid organ cancer. A June 2013 review article published in the "Quarterly Journal of Medicine" reported that high vitamin B12 levels most commonly occur with liver cancer. Other cancers that might cause:
- an elevated B12 level include lung
- possibly prostate cancer
It is thought that excess production of vitamin B12 carrier proteins by the tumors is the primary culprit for elevated levels. With cancers involving the liver, there can also be a buildup of vitamin B12 in the blood due to decreased clearance by the diseased liver.
- An elevated vitamin B12 level can be a nonspecific indicator of several types of solid organ cancer.
Anemia & Vitamin K
The liver is the main storage and clearance site for vitamin B12. High blood B12 levels can occur in liver conditions such as cirrhosis and hepatitis. Alcoholic liver disease is an example of a liver condition associated with high vitamin B12. With alcoholic liver disease, vitamin B12 as well as its carrier proteins can be elevated. One of the main causes of increased vitamin B12 with liver disease is release of stored vitamin by liver cells that have died due to the disorder. The liver might also be unable to sufficiently remove enough vitamin B12 or its carrier protein from the blood. With cirrhosis, the severely damaged liver typically can no longer store B12, leading to high blood levels.
- The liver is the main storage and clearance site for vitamin B12.
- With alcoholic liver disease, vitamin B12 as well as its carrier proteins can be elevated.
An increased blood level of vitamin B12 is sometimes caused by kidney disease, including diabetic kidney disease. There are a few different ways kidney disease is thought to contribute to high blood vitamin B12 levels. Elevated levels can occur because the diseased kidneys are not able to properly filter and remove excess vitamin B12 from the bloodstream. High vitamin B12 levels could also be explained by elevated vitamin B12 binding protein levels that are not filtered properly by the kidneys.
Reviewed by: Tina M. St. John, M.D.
- An increased blood level of vitamin B12 is sometimes caused by kidney disease, including diabetic kidney disease.
- High vitamin B12 levels could also be explained by elevated vitamin B12 binding protein levels that are not filtered properly by the kidneys.
Causes of Elevated B-12 Levels
Anemia & Vitamin K
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Vitamin B-12 Deficiency and the Spleen
Side Effects of 5000 IU of Vitamin D
- Holick MF, Gordon CM. Patient Guide to Vitamin D Deficiency. The Journal of Clinical Endocrinology & Metabolism. 2011;96(7):1-2. doi:10.1210/jcem.96.7.zeg33a
- Sunyecz JA. The use of calcium and vitamin D in the management of osteoporosis. Ther Clin Risk Manag. 2008;4(4):827-836. doi:10.2147/tcrm.s3552
- Giovannucci E, Liu Y, Hollis BW, Rimm EB. 25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study. Arch Intern Med. 2008;168(11):1174-1180. doi:10.1001/archinte.168.11.1174
- Gorham ED, Garland CF, Garland FC, et al. Optimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis. Am J Prev Med. 2007;32(3):210-216. doi:10.1016/j.amepre.2006.11.004
- Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. The American Journal of Clinical Nutrition. 2007;85(6):1586-1591. doi:10.1093/ajcn/85.6.1586
- Prentice RL, Pettinger MB, Jackson RD, et al. Health risks and benefits from calcium and vitamin D supplementation: Women’s Health Initiative clinical trial and cohort study. Osteoporos Int. 2013;24(2):567-580. doi:10.1007/s00198-012-2224-2
- Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010;91(5):1255-1260. doi:10.3945/ajcn.2009.29094
- Salehpour A, Hosseinpanah F, Shidfar F, et al. A 12-week double-blind randomized clinical trial of vitamin D₃ supplementation on body fat mass in healthy overweight and obese women. Nutr J. 2012;11:78. doi:10.1186/1475-2891-11-78
- Carrillo AE, Flynn MG, Pinkston C, et al. Impact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adults. Clin Nutr. 2013;32(3):375-381. doi:10.1016/j.clnu.2012.08.014
- Marcinowska-Suchowierska E, Kupisz-Urbańska M, Łukaszkiewicz J, Płudowski P, Jones G. Vitamin D Toxicity-A Clinical Perspective. Front Endocrinol. 2018;9:550. doi:10.3389/fendo.2018.00550
- Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011;96(1):53-58. doi:10.1210/jc.2010-2704
- Bouillon R, Van Schoor NM, Gielen E, et al. Optimal vitamin D status: a critical analysis on the basis of evidence-based medicine. J Clin Endocrinol Metab. 2013;98(8):E1283-E1304. doi:10.1210/jc.2013-1195
- American Academy of Dermatology. Position Statement of Vitamin D. 2010.
- Taksler GB, Cutler DM, Giovannucci E, Keating NL. Vitamin D deficiency in minority populations. Public Health Nutr. 2015;18(3):379-391. doi:10.1017/S1368980014000457
- Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930. doi:10.1210/jc.2011-0385
- Cannell JJ, Vieth R, Umhau JC, et al. Epidemic Influenza and Vitamin D. Epidemiol Infect. 2006; 134:1129-40.
- Carrillo AE1, Flynn MG, Pinkston C, Markofski MM, Jiang Y, Donkin SS, Teegarden D. Impact of Vitamin D Supplementation During a Resistance Training Intervention on Body Composition, Muscle Function, and Glucose Tolerance in Overweight and Obese Adults. Clin Nutr. 2013 Jun;32(3):375-81. doi: 10.1016/j.clnu.2012.08.014. Epub 2012 Aug 31.
- Ginde AA, Mansbach JM, Camargo CA, Jr. Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009; 169:384-90.
- Giovannucci E, Liu Y, Hollis BW, Rimm EB. 25-hydroxyvitamin D and Risk of Myocardial Infarction in Men: a Prospective Study. Arch Intern Med. 2008; 168:1174-80.
- Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF. Optimal Vitamin D Status for Colorectal Cancer Prevention: a Quantitative Meta-analysis. Am J Prev Med. 2007 Mar;32(3):210-6.
- Heaney, Robert P. “The Vitamin D Requirement in Health and Disease.” The Journal of Steroid Biochemistry & Molecular Biology 97 (2005):13-9.
- Holick MF. Vitamin D. In: Shils M, Olson J, Shike M, Ross AC, ed. Modern Nutrition in Health and Disease, 9th ed. Baltimore: Williams and Wilkins, 1999.
- National Institutes of Health Office of Dietary Supplements. Vitamin D: Dietary Supplement Fact Sheet. University of Ottawa Evidence-based Practice Center. Effectiveness and Safety of Vitamin D in Relation to Bone Health. Agency for Healthcare Research and Quality. Aug 2007: 07-E013.
- Salehpour A1, Hosseinpanah F, Shidfar F, Vafa M, Razaghi M, Dehghani S, Hoshiarrad A, Gohari M. A 12-week Double-blind Randomized Clinical Trial of Vitamin D₃ Supplementation on Body Fat Mass in Healthy Overweight and Obese Women. Nutr J. 2012 Sep 22;11:78. doi: 10.1186/1475-2891-11-78.
- Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza A in Schoolchildren. Am J Clin Nutr. 2010 91:1255-60. Epub 2010 Mar 10.
- Wilkins, Consuelo H. and Yvette I. Sheline, et al. “Vitamin D Deficiency Is Associated with Low Mood and Worse Cognitive Performance in Older Adults.” American Journal of Geriatric Psychiatry 14 (2006): 1032-40.
Leann Mikesh holds a Ph.D. in pathology. She has trained at the University of Virginia Medical Laboratories and has over 15 years experience in clinical, cancer and immunology research. Dr. Mikesh performed kidney and bone marrow transplantation compatibility testing to put herself through graduate school.