Impact of Vitamin D3 Supplementation on Motor Functionality and the Immune Response in Parkinson's Disease Patients with Vitamin D Deficiency

The purpose of this study was to investigate the levels of vitamin D, regulatory T (Treg) cells, and T helper 17 (Th17) cells in the peripheral blood of patients with Parkinson's disease(PD), explore their potential relationships with PD, and further examine the effects of vitamin D intervention on these biomarkers and clinical outcomes. PD patients with low vitamin D3 levels were randomly assigned to two groups: those supplemented with vitamin D3 (VitD3, n=15) and those treated with vegetable oil (PL, n=15). Treatment was administered continuously for 3 months. Vitamin D3, Th17 and Treg levels and related clinical scales were continuously monitored and evaluated. The results revealed that the level of 25(OH) D3 in the peripheral blood increased in the VitD3 group, and the Th17 and Treg levels tended toward those of the normal population. Compared with those of the preintervention groups and the PL group after the 3-month follow-up, motor function improved in the VitD3 group. Additionally, vitamin D was negatively correlated with Th17 cells and positively correlated with Treg cells. In PD patients, motor function was positively correlated with vitamin D and Treg levels but negatively correlated with Th17 levels. We believe that it is necessary for PD patients with low vitamin D levels to supplement vitamin D to normal levels.