Assessment of Vitamin B12 Efficacy on Cognitive Memory Function and Depressive Symptoms: A Systematic Review and Meta-Analysis.

Vitamin B12 is significant for DNA synthesis, red blood cell formation, and nervous system function. Inadequate vitamin B12 levels may result in a higher risk of depression, necessitating the need for supplementation to improve mood and cognitive function. However, the use of vitamin B12 supplementation varies across studies. This review aims to evaluate the effect of vitamin B12 supplementation on cognitive memory function and depressive symptoms among participants who may have mild cognitive impairment (MCI). This review adhered to the Cochrane Handbook and PRISMA guidelines. A comprehensive search was conducted across PubMed, CENTRAL, Medline, and Ovid, with no constraints on geography or demographics, up to August 31, 2024. Only randomized controlled trials (RCTs) were included. Data on study characteristics, treatment details, and outcomes were extracted. The risk of bias was assessed using the revised Cochrane ROB2 tool. A meta-analysis of the effect of vitamin B12 on cognitive memory and depression was conducted using Jamovi software (The jamovi project (2024). jamovi (Version 2.5) [Computer Software]. Retrieved from https://www.jamovi.org). Statistical significance was set at p < 0.05. The results yielded 483 records that were screened based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Excluding duplicates and irrelevant studies, the meta-analysis finally included nine RCTs. For cognitive memory function, eight of the nine included studies were analyzed, showing an average standardized mean difference of -0.03 (95% confidence interval (CI): -0.07 to 0.01), indicating no significant effect of vitamin B12 supplementation (p = 0.1801) and no significant heterogeneity. Regarding depressive symptoms, three of the nine included studies were analyzed, yielding an average standardized mean difference of -0.01 (95% CI: -0.0773 to 0.0525), also showing no significant effect (p = 0.708). These results suggest that vitamin B12 complex supplementation has an insignificant effect on cognitive function and depressive symptoms in the general population. However, further research is needed to explore the conditions under which B12 is most effective, providing clearer guidelines for its use in clinical practice.