Evidence map›Paper›PMID 33809274›Full record

SynthesisNutrients2021

Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.

Stefan Markun, Isaac Gravestock, Levy Jäger, Thomas Rosemann, Giuseppe Pichierri, Jakob M Burgstaller

Registry-linked trialOpen access · goldAbstract readMeta-AnalysisSystematic Review
In one paragraph

Synthesis in Nutrients, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05931965 (Comparative Efficacy of Antidepressants With L-methylfolate, B12, and Magnesium in Depressive Disorders), which is not on this map. Cited by 45 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
45citing papers in PubMed, 3 pooled it
13.9field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05931965 nacompletednot on this mapstarted 2022, after this paper: background citation

Comparative Efficacy of Antidepressants With L-methylfolate, B12, and Magnesium in Depressive Disorders

TypeinterventionalSponsorRiphah International UniversityRan2022 to 2023Enrolled88ConditionsDepressionArmsL-methylfolate, Vitamin B12, magnesium
3 · Its place in the literature

Who cites it

45 citing papers in PubMed, 3 syntheses or guidelines pooled it, 105 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Pooled it
  4. Trial
  5. Article
  6. Vitamin BNutrients · 2026
    Review
  7. Vitamin D and Vitamin BDiseases (Basel, Switzerland) · 2026
    Review
  8. Review
  9. Article
  10. Review
  11. Article
  12. Article
  13. Higher vitamin BAlzheimer's & dementia : the journal of the Alzheimer's Association · 2025
    Article
  14. Review
  15. Review
  16. Article
  17. Article
  18. Article
  19. Review
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors at 2 institutions in 1 country.

Stefan MarkunInstitute of Primary Care, University and University Hospital Zurich, 8091 Zurich, Switzerland.
Isaac GravestockHorten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich, 8091 Zurich, Switzerland.
Levy JägerInstitute of Primary Care, University and University Hospital Zurich, 8091 Zurich, Switzerland.ORCID 0000-0002-7749-6759
Thomas RosemannInstitute of Primary Care, University and University Hospital Zurich, 8091 Zurich, Switzerland.ORCID 0000-0002-6436-6306
Giuseppe PichierriInstitute of Primary Care, University and University Hospital Zurich, 8091 Zurich, Switzerland.ORCID 0000-0002-3582-5219
Jakob M BurgstallerInstitute of Primary Care, University and University Hospital Zurich, 8091 Zurich, Switzerland.
University Hospital of Zurich · CHUniversity of Zurich · CH

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12 deficiency or advanced neurological disorders and the effectiveness of vitamin B12 supplementation in such cases is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to assess the effects of vitamin B12 alone (B12 alone), in addition to vitamin B12 and folic acid with or without vitamin B6 (B complex) on cognitive function, depressive symptoms, and idiopathic fatigue in patients without advanced neurological disorders or overt vitamin B12 deficiency. Medline, Embase, PsycInfo, Cochrane Library, and Scopus were searched. A total of 16 RCTs with 6276 participants were included. Regarding cognitive function outcomes, we found no evidence for an effect of B12 alone or B complex supplementation on any subdomain of cognitive function outcomes. Further, meta-regression showed no significant associations of treatment effects with any of the potential predictors. We also found no overall effect of vitamin supplementation on measures of depression. Further, only one study reported effects on idiopathic fatigue, and therefore, no analysis was possible. Vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.

Indexed as

Dietary SupplementsCognitionDepressionFatigueHumansVitamin B 12VitaminsVitamin B 12Vitaminscognitive functiondepressive symptomsfatiguemeta-analysisRCTvitamin B12

Identifiers

PMID33809274
PMCPMC8000524
OpenAlexW3136065697

What Socratic holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.