Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia

Cureus. 2020 Feb 13;12(2):e6976. doi: 10.7759/cureus.6976.


Background Vitamin B12 deficiency is linked to impaired cognition and memory along with a sensation of tingling and numbness, an outcome of poor myelination. Elevated methylmalonic acid and serum homocysteine levels are markers of Vitamin B12 deficiency. Elevated homocysteine levels are also often associated with Alzheimer's disease and stroke. We conducted this study to determine the effect of vitamin B12 replacement therapy on vitamin B12-deficient patients with noted cognitive impairment. Methods We conducted a cross-sectional, multicenter study of patients with minimal cognitive impairment (MCI) to assess for Vitamin B12 and homocysteine levels. All patients found to be deficient in vitamin B12 underwent replacement therapy and were assessed again after three months via the Mini-Mental State Examination (MMSE) and a review of symptoms. Results A total of 202 patients were included in the study. Of those, 171 (84%) patients reported marked symptomatic improvement after vitamin B12 replacement while MMSE scores improved in 158 (78%) patients. Of the remaining 44 patients who reported no symptomatic improvement, MMSE scores improved in 26 while 18 patients showed no MMSE score improvements. Conclusions Vitamin B12 deficiency is linked to cognition, and replacement therapy may be an option to improve patient cognition outcomes. Further studies are needed to confirm and refine the observed associations over a larger scale and to determine whether these findings will translate to a reduction in cognitive decline.

Keywords: acetyl homocysteine; cognition; memory deficit; mental health; vitamin b12 deficiency.