Cognitive impairment and vitamin B12 : a review

Moore, Eileen, Mander, Alastair, Ames, David, Carne, Ross, Sanders, Kerrie and Watters, David 2012, Cognitive impairment and vitamin B12 : a review, International psychogeriatrics, vol. 24, no. 4, pp. 541-548, doi: 10.1017/S1041610211002511.

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Title Cognitive impairment and vitamin B12 : a review
Author(s) Moore, Eileen
Mander, Alastair
Ames, David
Carne, Ross
Sanders, Kerrie
Watters, DavidORCID iD for Watters, David
Journal name International psychogeriatrics
Volume number 24
Issue number 4
Start page 541
End page 548
Total pages 8
Publisher Cambridge University Press
Place of publication Cambridge, England
Publication date 2012-04
ISSN 1041-6102
Keyword(s) dementia
molecular biology
cognitive disorders
Alzheimer's disease (AD)
Summary Background: This review examines the associations between low vitamin B12 levels, neurodegenerative disease, and cognitive impairment. The potential impact of comorbidities and medications associated with vitamin B12 derangements were also investigated. In addition, we reviewed the evidence as to whether vitamin B12 therapy is efficacious for cognitive impairment and dementia.

Methods: A systematic literature search identified 43 studies investigating the association of vitamin B12 and cognitive impairment or dementia. Seventeen studies reported on the efficacy of vitamin B12 therapy for these conditions.

Results: Vitamin B12 levels in the subclinical low-normal range (<250 ρmol/L) are associated with Alzheimer's disease, vascular dementia, and Parkinson's disease. Vegetarianism and metformin use contribute to depressed vitamin B12 levels and may independently increase the risk for cognitive impairment. Vitamin B12 deficiency (<150 ρmol/L) is associated with cognitive impairment. Vitamin B12 supplements administered orally or parenterally at high dose (1 mg daily) were effective in correcting biochemical deficiency, but improved cognition only in patients with pre-existing vitamin B12 deficiency (serum vitamin B12 levels <150 ρmol/L or serum homocysteine levels >19.9 μmol/L).

Conclusion: Low serum vitamin B12 levels are associated with neurodegenerative disease and cognitive impairment. There is a small subset of dementias that are reversible with vitamin B12 therapy and this treatment is inexpensive and safe. Vitamin B12 therapy does not improve cognition in patients without pre-existing deficiency. There is a need for large, well-resourced clinical trials to close the gaps in our current understanding of the nature of the associations of vitamin B12 insufficiency and neurodegenerative disease.
Language eng
DOI 10.1017/S1041610211002511
Field of Research 110399 Clinical Sciences not elsewhere classified
Socio Economic Objective 970111 Expanding Knowledge in the Medical and Health Sciences
HERDC Research category C1 Refereed article in a scholarly journal
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Document type: Journal Article
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