Evaluation of surrogate biomarkers of memory and cognition in aging adults with vitamin B12 deficiency: A cross-sectional study.

Background: Vitamin B12 (Vit B12) is a cofactor in one-carbon metabolism, methylation reactions, myelin synthesis, and neuronal function. Its deficiency can lead to neurodegeneration and cognitive decline. This study aims to evaluate cognitive and memory-related biomarkers in otherwise healthy aging adults with vitamin B12 deficiency and to explore whether it is an under recognized contributor to dementia. Methods: Serum levels of Aβ42, acetylcholinesterase (AChE), brain derived neurotrophic factor (BDNF), GSH, and calcium were estimated in ninety healthy individuals, aged between 45 to 65 years. They were divided into 3 groups of 30 participants each, as vit B12 sufficient (>300 pg/ml), insufficient (201-300 pg/ml) and deficient (≤200pg/ml) groups. Serum BDNF and Aβ42 were estimated by sandwich ELISA. Calcium, GSH and AChE were measured spectrophotometrically. Results: Aβ42 levels showed a significant increase in both insufficient and deficient groups relative to the sufficient group (p<0.001) There was an apparent decrease in BDNF levels and a significant decline in AChE levels in the deficient group compared to the sufficient group (p=0.029). There was a more pronounced decrease in GSH in the deficient group (p<0.001) compared to the sufficient group. Notably, serum calcium levels demonstrated a significant increase in the insufficient group followed by normalization in the deficient group. Conclusion: Overall, the findings indicate that Vit B12 deficiency is associated with significant alterations in cognitive biomarkers and oxidative stress causing neuronal loss, which may contribute to memory deficits and cognitive decline. Therefore, vitamin B12 deficiency may be a significant, modifiable risk factor for dementia.