Cognitive impairment and vitamin B12: A review

Abstract

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 assoc..