Vitamin D and Parkinson's Disease

Vitamin D is a fat-soluble secosteroid, traditionally considered a key regulator of bone metabolism, calcium and phosphorous homeostasis. Its action is made possible through the binding to the vitamin D receptor (VDR), after which it directly and indirectly modulates the expression of thousands of genes. Vitamin D is important for brain development, mature brain activity and associated with many neurological diseases, including Parkinson's disease (PD). High frequency of vitamin D deficiency in patients with Parkinson's disease compared to control population was noted nearly twenty years ago. This finding is of interest given vitamin D's neuroprotective effect, exerted by the action of neurotrophic factors, regulation of nerve growth or through protection against cytotoxicity. Vitamin D deficiency seems to be related to disease severity and disease progression, evaluated by Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (H&Y) scale, but not with age of PD onset and duration of disease. Additionally, fall risk has been associated with lower vitamin D levels in PD. However, while the association between vitamin D and motor-symptoms seems to be possible, results of studies investigating the association with non-motor symptoms are conflicting. In addition, very little evidence exists regarding the possibility to use vitamin D supplementation to reduce clinical manifestations and disability in patients with PD. However, considering the positive balance between potential benefits against its limited risks, vitamin D supplementation for PD patients will probably be considered in the near future, if further confirmed in clinical studies.

Automated summary

Vitamin D plays a crucial role in bone metabolism, calcium and phosphorous homeostasis, as well as brain development and neuroprotection. Patients with Parkinson's disease often have a high frequency of vitamin D deficiency, which may be related to disease severity and progression. However, the evidence regarding the use of vitamin D supplementation to reduce symptoms and disability in patients with Parkinson's disease is limited. Further clinical studies are needed to confirm the potential benefits and risks of vitamin D supplementation in this population.