In summary, as low serum 25(OH)D levels might be correlated with an increased risk of developing PD, higher 25(OH)D levels seems to be associated with better motor symptoms, especially with improved balance control. It is not yet clear if vitamin D is related to the severity of symptoms of PD and with clinical progression; therefore, its role as disease progression biomarker for PD is not yet clear. Further studies are needed to establish the role of vitamin D etiology of PD, and its relationship with motor and non-motor symptoms, quality of life and progression of disease.
It is not yet proven if vitamin D reintegration could be an appropriate support to
pharmacological and rehabilitative therapy in PD patients. However, though insufficient evidence is available to introduce vitamin D as supportive therapy in PD patients, considering its limited risks, we are confident enough to insinuate, as a dietary intervention, that vitamin D supplementation would act at three different levels: (1) improve public
health considering its possible role in brain development and its influence in pathogenesis of many neurological disorders, including PD; (2) slowing down the worsening of some PD symptoms; (3) finally, considering the increased risk of falls during disease progression,
reduce the risk of fracture in PD patients.