Abstract
- Background
Vitamin $\text{B}_{12}$ is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin $\text{B}_{12}$ deficiency or advanced neurological disorders, and the effectiveness of vitamin $\text{B}_{12}$ supplementation in such cases is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to assess the effects of vitamin $\text{B}_{12}$ alone ($\text{B}_{12}\text{ alone}$), as well as vitamin $\text{B}_{12}$ and folic acid with or without vitamin $\text{B}_6$ ($\text{B complex}$), on cognitive function, depressive symptoms, and idiopathic fatigue in patients without advanced neurological disorders or overt vitamin $\text{B}_{12}$ deficiency.
- Methods
Medline, Embase, PsycInfo, Cochrane Library, and Scopus were searched. A total of 16 RCTs with 6,276 participants were included.
- Results
Regarding cognitive function outcomes, we found no evidence for an effect of $\text{B}_{12}\text{ alone}$ or $\text{B complex}$ 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.
- Conclusions
Vitamin $\text{B}_{12}$ supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders or overt vitamin $\text{B}_{12}$ deficiency.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8000524/