Structural and Functional Brain Changes Associated with Vitamin B12 Deficiency using Magnetic Resonance Imaging: A Systematic Review and Meta-analysis

Aim: This review was conducted to assess the structural and functional brain changes associated with vitamin B12 deficiency in different age groups using MRI. Methods: PubMed, Embase, Medline, CINAHL, Scopus, Web of Science, and Google Scholar were searched for magnetic resonance imaging (MRI) studies that explored structural and functional brain changes associated with vitamin B12 deficiency in different age groups. The inclusion criteria were as follows: (1) the population consisted of people and not animals; (2) patients with known B12 deficiency; (3) English publications; (3) at least one of the following brain MRI techniques had been employed: VBM, DWI, DTI, fMRI, or rs-fMRI. However, case reports, systematic reviews and meta-analyses were excluded. Results: Twelve articles met the inclusion criteria. The results of my review show a connection between vitamin B12 deficiency and abnormal structural and functional brain changes in several brain regions. These changes were observed in different age groups ranging from a mean age of seven years to a mean age in the 70s. The results also highlight the association between brain changes and cognitive decline among affected subjects. Improvements in damaged brain regions post-vitamin B12 treatment were also studied. Conclusion: Structural and functional brain damage was found to be associated with vitamin B12 deficiency in all age groups. Vitamin B12 treatment may lead to partial or complete structural and/or functional recovery, as well as a cognitive recovery.