Vitamin D3 (Cholecalciferol) for Parkinson's Disease
Also known as: Cholecalciferol, Calcitriol, 25-hydroxyvitamin D
Low vitamin D is common in PD patients and may contribute to disease progression through impaired dopaminergic neuron maintenance.
Mechanism of Action
VDR is expressed in substantia nigra neurons. Vitamin D upregulates tyrosine hydroxylase (rate-limiting enzyme for dopamine synthesis), enhances GDNF expression for dopaminergic neuron survival, and modulates neuroinflammation through T-regulatory cell induction.
General mechanism: Secosteroid hormone. VDR-mediated gene transcription affecting calcium, immunity, neurotrophic factors, cell differentiation, and apoptosis.
Current Evidence
Higher vitamin D associated with reduced PD risk in meta-analyses. Supplementation trial in PD showed slowed Hoehn-Yahr progression. 1200 IU/day showed benefit vs placebo.
Clinical Status: Phase II positive. Supplementation recommended for PD patients with deficiency.
Safety Profile
Safe at recommended doses (1000-4000 IU/day). Hypercalcemia at very high doses. Monitor 25(OH)D levels. Rare: kidney stones.
Key Research Questions
- Does vitamin D supplementation slow motor progression in PD?
- Can vitamin D3 enhance GDNF-mediated dopaminergic neuroprotection?