Efficacy of Vitamin B Supplementation on Cognition in Elderly Patients With Cognitive-Related Diseases

J Geriatr Psychiatry Neurol. 2017 Jan;30(1):50-59. doi: 10.1177/0891988716673466. Epub 2016 Oct 17.


Increase in serum homocysteine is shown to be a potential risk factor for cognitive impairment. Evidence suggests that vitamin B supplementation may reduce cognitive decline by lowering the homocysteine levels. The current meta-analysis evaluated the efficacy of folic acid along with vitamin B12 and/or B6 in lowering homocysteine, thereby attenuating cognitive decline in elderly patients with Alzheimer disease or dementia. Randomized controlled trials (RCTs) comparing the efficacy of folate and B vitamin supplementation in patients with cognitive decline secondary to Alzheimer disease or dementia were identified using the keywords, "homocysteine, hyper-homocysteinemia, B vitamin, vitamin B6, B12, folic acid, cognitive, Alzheimer's disease, and dementia." The outcome measures analyzed were the Mini-Mental State Examination (MMSE) score and serum homocysteine. Of the 77 studies identified, 4 RCTs were included in the current meta-analysis. The baseline characteristics, age, and gender distribution of patients among the 2 groups (supplement vs placebo) were comparable. The results reveal that the intervention group achieved significantly greater reduction in homocysteine levels than the control (pooled difference in means = -3.625, 95% confidence interval [CI] = -5.642 to -1.608, P < .001). However, no significant difference in MMSE (pooled difference in means = 0.027, 95% CI = -0.518 to 0.573, P = 0.921) was observed between the groups. Taken together, vitamin B supplementation was effective in reducing serum homocysteine levels. However, it did not translate into cognitive improvement, indicating that the existing data on vitamin B-induced improvement in cognition by lowering homocysteine levels are conflicting.

Keywords: aged; cognitive disorders; folic acid; homocysteine; vitamin B 6; vitamin B12.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / drug therapy*
  • Alzheimer Disease / etiology
  • Cognition / drug effects*
  • Cognition Disorders / blood
  • Cognition Disorders / drug therapy*
  • Cognition Disorders / etiology
  • Dementia / drug therapy*
  • Dementia / etiology
  • Dietary Supplements
  • Drug Therapy, Combination
  • Female
  • Folic Acid / blood
  • Folic Acid / therapeutic use*
  • Homocysteine / blood*
  • Homocysteine / drug effects
  • Humans
  • Male
  • Middle Aged
  • Randomized Controlled Trials as Topic
  • Vitamin B 12 / blood
  • Vitamin B 12 / therapeutic use*
  • Vitamin B 6 / blood
  • Vitamin B 6 / therapeutic use*
  • Vitamin B Complex / blood
  • Vitamin B Complex / therapeutic use*


  • Homocysteine
  • Vitamin B Complex
  • Vitamin B 6
  • Folic Acid
  • Vitamin B 12