Parkinsonism Relat Disord. 2008;14(4):321-5. Epub 2007 Dec 4.
Folate and vitamin B12 levels in levodopa-treated Parkinson's disease patients: their relationship to clinical manifestations, mood and cognition.
Triantafyllou NI, et al
Source
Athens University Medical School, Athens, Greece.
Abstract
We tested the hypothesis that mood, clinical manifestations and cognitive impairment of levodopa-treated Parkinson's disease (PD) patients are associated with vitamin B12 and folate deficiency. To this end, we performed this cross-sectional study by measuring serum folate and vitamin B12 blood levels in 111 consecutive PD patients. Levodopa-treated PD patients showed significantly lower serum levels of folate and vitamin B12 than neurological controls, while depressed patients had significantly lower serum folate levels as compared to non-depressed. Cognitively impaired PD patients exhibited significantly lower serum vitamin B12 levels as compared to cognitively non-impaired. In conclusion, lower folate levels were associated with depression, while lower vitamin B12 levels were associated with cognitive impairment. The effects of vitamin supplementation merit further attention and investigation.

Thank you for that article . I often wondered about that. I take H2 blockers which block the absorption of those vit. Suppose supplement is in order.