Annals of Indian Academy of Neurology
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Table of Contents
Year : 2015  |  Volume : 18  |  Issue : 4  |  Page : 494-495

Vitamin B12 and cognitive decline

1 Department of Neurology, Beytepe Military Hospital, Ankara, Turkey
2 Department of Neurology, Gulhane Military Medical Academy, Ankara, Turkey

Date of Submission09-Aug-2015
Date of Decision01-Sep-2015
Date of Acceptance01-Sep-2015
Date of Web Publication17-Nov-2015

Correspondence Address:
Serdar Tasdemir
Department of Neurology, Beytepe Military Hospital, Cankaya - 06805, Ankara
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-2327.169683

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How to cite this article:
Tasdemir S, Ulas UH. Vitamin B12 and cognitive decline. Ann Indian Acad Neurol 2015;18:494-5

How to cite this URL:
Tasdemir S, Ulas UH. Vitamin B12 and cognitive decline. Ann Indian Acad Neurol [serial online] 2015 [cited 2020 Feb 24];18:494-5. Available from:


We have read the study of Tejal Kanhaiya Vedak et al. entitled "Vitamin D as a marker of cognitive decline in elderly Indian population" with great interest. [1] In this study, they aimed to assess the serum levels of 25-hydroxyvitamin D [25(OH)D] and its association with markers of cognitive impairment and homocysteine levels in the elderly Indian population. [1]

They reported significantly decreased concentration of 25(OH)D and increased concentration of homocysteine in the serum of patients with dementia when compared to age-matched controls and patients with mild cognitive impairment (MCI) and also reported that an association of serum levels of vitamin D with markers of cognitive decline as well as serum homocysteine levels was observed in patients with dementia and MCI when compared to controls. [1]

When we inspected the article in the model of the study, we found that all subjects were evaluated with analysis of blood glucose levels, lipid profile, serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and venereal disease research laboratory test (VDRL), and thyroid profile [triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH)] on fresh serum and in hematology, erythrocyte sedimentation rate (ESR), and complete blood count (CBC) were performed. [1] We noticed that the authors did not consider vitamin B12 levels.

The studies showed that low normal concentrations of vitamin B12 might be associated with cognitive impairment [2],[3] Hin et al. evaluated a total of 1,000 individuals aged 75 years and above and they reported that low vitamin B12 concentrations were associated with cognitive impairment in older people in the absence of anemia [4] In a longitudinal cohort study evaluating 1,648 participants, it was shown that low vitamin B12 status was significantly associated with a more rapid cognitive decline during a 10-year period [5] In the deficiency of vitamin B12, there are many possible mechanisms by which brain function is affected. One possibility is homocysteine because low vitamin B12 status is associated with an elevation of the concentration of homocysteine and homocysteine has an effect on the cerebral vasculature. [6],[7] Alternatively, it was concluded that the high prevalence of methylmalonic acid, a marker of vitamin B12 deficiency, in the elderly is associated with lower cognitive function scores and particularly with lower scores of language comprehension and expression. [8] On the other hand, it is stated that vitamin B12 deficiency is accompanied by alterations in the concentrations of cytokines such as epidermal growth factor and tumor necrosis factor-α.[9],[10] By these information from the literature, a few questions arise about evaluating the individuals for study. Did the authors evaluate vitamin B12 in the study group? If yes, this issue should be declared by the authors in our opinion. If not, readers should keep in mind that vitamin B12 deficiency might have an effect on the cognitive function of the brain.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Vedak TK, Ganwir V, Shah AB, Pinto C, Lele VR, Subramanyam A, et al. Vitamin D as a marker of cognitive decline in elderly Indian population. Ann Indian Acad Neurol 2015:18:314-9.  Back to cited text no. 1
Bell IR, Edman JS, Marby DW, Satlin A, Dreier T, Liptzin B, et al. Vitamin B12 and folate status in acute geropsychiatric inpatients: Affective and cognitive characteristics of a vitamin nondeficient population. Biol Psychiatry 1990;27:125-37.   Back to cited text no. 2
Rosenberg IH, Miller JW. Nutritional factors in physical and cognitive functions of elderly people. Am J Clin Nutr 1992;55(Suppl):1237-43S.  Back to cited text no. 3
Hin H, Clarke R, Sherliker P, Atoyebi W, Emmens K, Birks J, et al. Clinical relevance of low serum vitamin B12 concentrations in older people: The Banbury B12 study. Age Ageing 2006;35:416-22.  Back to cited text no. 4
Clarke R, Birks J, Nexo E, Ueland PM, Schneede J, Scott J, et al. Low vitamin B-12 status and risk of cognitive decline in older adults. Am J Clin Nutr 2007;86:1384-91.  Back to cited text no. 5
Refsum H, Nurk E, Smith AD, Ueland PM, Gjesdal CG, Bjelland I, et al. The hordaland homocysteine study: A community-based study of homocysteine, its determinants, and associations with disease. J Nutr 2006;136(Suppl):1731-40S.  Back to cited text no. 6
Obeid R, Herrmann W. Mechanisms of homocysteine neurotoxicity in neurodegenerative diseases with special reference to dementia. FEBS Lett 2006;580:2994-3005.   Back to cited text no. 7
McCracken C, Hudson P, Ellis R, McCaddon A; Medical Research Council Cognitive Function and Ageing Study. Methylmalonic acid and cognitive function in the Medical Research Council Cognitive Function and Ageing Study. Am J Clin Nutr 2006; 84:1406-11.  Back to cited text no. 8
Scalabrino G, Veber D, Mutti E. Experimental and clinical evidence of the role of cytokines and growth factors in the pathogenesis of acquired cobalamin-deficient leukoneuropathy. Brain Res Rev 2008;59:42-54.  Back to cited text no. 9
Smith AD, Refsum H. Vitamin B-12 and cognition in the elderly. Am J Clin Nutr 2009;89:707-11S.  Back to cited text no. 10


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