https://www.mayoclinicproceedings.or...177-6/fulltext



Vitamin B12 is lower in patients with PD compared with controls, and low levels have been associated with peripheral neuropathy, cognitive impairment, and more rapid rate of disease progression in PD.vitamin B12 may lead to reduced availability of choline as a substrate for cholinergic transmission. Here we will review the proposed pathophysiology of nonmotor symptoms in PD and the potential relationship between vitamin B12 and acetylcholine metabolism. We propose that vitamin B12 supplementation could be considered as an adjuvant approach to improve cholinergic transmission and, potentially, motor and cognitive function in patients with PD.