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Update on vitamin B12 deficiency.
Am Fam Physician 2011; 83(12):1425-30AF

Abstract

Vitamin B(12) (cobalamin) deficiency is a common cause of megaloblastic anemia, a variety of neuropsychiatric symptoms, and elevated serum homocysteine levels, especially in older persons. There are a number of risk factors for vitamin B(12) deficiency, including prolonged use of metformin and proton pump inhibitors. No major medical organizations, including the U.S. Preventive Services Task Force, have published guidelines on screening asymptomatic or low-risk adults for vitamin B(12) deficiency, but high-risk patients, such as those with malabsorptive disorders, may warrant screening. The initial laboratory assessment of a patient with suspected vitamin B(12) deficiency should include a complete blood count and a serum vitamin B(12) level. Measurements of serum vitamin B(12) may not reliably detect deficiency, and measurement of serum homocysteine and/or methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low normal levels of vitamin B(12). Oral administration of high-dose vitamin B(12) (1 to 2 mg daily) is as effective as intramuscular administration in correcting the deficiency, regardless of etiology. Because crystalline formulations are better absorbed than naturally occurring vitamin B(12), patients older than 50 years and strict vegetarians should consume foods fortified with vitamin B(12) and vitamin B(12) supplements, rather than attempting to get vitamin B(12) strictly from dietary sources. Administration of vitamin B(12) to patients with elevated serum homocysteine levels has not been shown to reduce cardiovascular outcomes in high-risk patients or alter the cognitive decline of patients with mild to moderate Alzheimer disease.

Authors+Show Affiliations

St. Luke's Hospital, Bethlehem, PA, USA. langanr@slhn.orgNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

21671542

Citation

Langan, Robert C., and Kimberly J. Zawistoski. "Update On Vitamin B12 Deficiency." American Family Physician, vol. 83, no. 12, 2011, pp. 1425-30.
Langan RC, Zawistoski KJ. Update on vitamin B12 deficiency. Am Fam Physician. 2011;83(12):1425-30.
Langan, R. C., & Zawistoski, K. J. (2011). Update on vitamin B12 deficiency. American Family Physician, 83(12), pp. 1425-30.
Langan RC, Zawistoski KJ. Update On Vitamin B12 Deficiency. Am Fam Physician. 2011 Jun 15;83(12):1425-30. PubMed PMID: 21671542.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Update on vitamin B12 deficiency. AU - Langan,Robert C, AU - Zawistoski,Kimberly J, PY - 2011/6/16/entrez PY - 2011/6/16/pubmed PY - 2013/2/23/medline SP - 1425 EP - 30 JF - American family physician JO - Am Fam Physician VL - 83 IS - 12 N2 - Vitamin B(12) (cobalamin) deficiency is a common cause of megaloblastic anemia, a variety of neuropsychiatric symptoms, and elevated serum homocysteine levels, especially in older persons. There are a number of risk factors for vitamin B(12) deficiency, including prolonged use of metformin and proton pump inhibitors. No major medical organizations, including the U.S. Preventive Services Task Force, have published guidelines on screening asymptomatic or low-risk adults for vitamin B(12) deficiency, but high-risk patients, such as those with malabsorptive disorders, may warrant screening. The initial laboratory assessment of a patient with suspected vitamin B(12) deficiency should include a complete blood count and a serum vitamin B(12) level. Measurements of serum vitamin B(12) may not reliably detect deficiency, and measurement of serum homocysteine and/or methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low normal levels of vitamin B(12). Oral administration of high-dose vitamin B(12) (1 to 2 mg daily) is as effective as intramuscular administration in correcting the deficiency, regardless of etiology. Because crystalline formulations are better absorbed than naturally occurring vitamin B(12), patients older than 50 years and strict vegetarians should consume foods fortified with vitamin B(12) and vitamin B(12) supplements, rather than attempting to get vitamin B(12) strictly from dietary sources. Administration of vitamin B(12) to patients with elevated serum homocysteine levels has not been shown to reduce cardiovascular outcomes in high-risk patients or alter the cognitive decline of patients with mild to moderate Alzheimer disease. SN - 1532-0650 UR - https://www.unboundmedicine.com/medline/citation/21671542/full_citation L2 - http://www.aafp.org/link_out?pmid=21671542 DB - PRIME DP - Unbound Medicine ER -