Vitamin D Deficiency and Parkinson's

Reviewed by: HU Medical Review Board | Last reviewed: March 2017 | Last updated: April 2020

Vitamin D is an essential element that is present in very few foods. It is generally consumed as a dietary supplement or produced by the body in the presence of sunlight. Ultraviolet rays on the skin triggers vitamin D synthesis. All cells in the body, including brain cells (neurons), have vitamin D receptors. While it is well known that vitamin D promotes calcium absorption in the gut and plays an important role in bone health, its role in the brain is less understood.1,2

Vitamin D deficiency is common among people living with Parkinson’s disease (PD). It is not clear whether people living with PD have more vitamin D deficiency because they get out less and have less sun exposure, or if there is some disease mechanism that causes less vitamin D in the body. A deficiency in vitamin D can lead to complications, such as weakened bones. People with PD who have a deficiency in vitamin D may be at increased risk of bone fracture.1,3

Vitamin D and the risk of developing Parkinson’s disease

Some studies have suggested that higher levels of vitamin D may be associated with a lower risk of developing PD, or conversely, that low levels of vitamin D might be related to an increased risk of developing Parkinson’s. While research has found that people with higher levels of vitamin D seem to have a reduced risk of PD, science cannot yet pinpoint if vitamin D specifically has a preventive effect.4

Vitamin D and certain genetic types

Taking supplements of vitamin D may help some patients with PD, particularly those with specific genetic backgrounds. A clinical trial that studied vitamin D supplements found that people with particular gene versions, called Fokl TT and Fokl CT, benefitted from taking vitamin D while those with the gene version Fokl CC did not get a benefit. More research is needed, but it appears that vitamin D may play a role in slowing the progression of PD in some patients.5,6

Vitamin D and orthostatic hypotension

Low levels of vitamin D have also been associated with orthostatic hypotension, the severe drop in blood pressure that occurs upon standing, in people with PD. Orthostatic hypotension can be dangerous, as it can cause dizziness or a loss of consciousness, and may lead to falls and injury. One study found that those patients with PD who experienced orthostatic hypotension were more likely to have low levels of vitamin D, compared to those patients with PD who did not experience orthostatic hypotension. However, the underlying reasons for this are not yet clear.7

Should you take a vitamin D supplement?

Currently, there are no guidelines on vitamin D supplementation for people with PD, and each individual patient should discuss supplementation with their healthcare provider. Healthcare providers can determine your level of vitamin D through a blood test, and supplementation is recommended to protect bone health in people with deficient levels of the vitamin.1,3

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