A new study published in the Archives of Neurology has discovered that high levels of vitamin D, the sunshine vitamin, may have a protective effect against Parkinson's disease. The reason for this is because vitamin D may influence certain important neurological pathways in the brain, specifically the dopaminergic neurons.

To further examine this link, researchers enrolled 3,173 men and women between the ages of 50 and 79 years who did not have the condition at the beginning of the study. Background information was obtained regarding the subject's health and socioeconomic status, and a baseline physical was performed, which included measuring blood levels of vitamin D.

Over the course of 29 years (up to 2007), 50 of the subjects developed Parkinson's disease. When the scientists adjusted for relevant factors, including their level of activity and the weight (as measured by body mass index, or BMI), they discovered that those individuals who had the highest levels of vitamin D in their blood had a 67 percent lower risk for developing Parkinson's disease when compared with those with the lowest levels of vitamin.

The study was carried out in Finland, where it is common for people to suffer from a lack of sunlight exposure, thus predisposing them to chronically low levels of vitamin D. In fact, the average level of the vitamin was about half of the recommended level. Coupled with the fact that a dose-response relationship was observed, the data suggests that inadequate vitamin D levels may indeed be involved in the onset of Parkinson's disease.

While the exact physiological mechanism behind this phenomenon is still not completely understood, the vitamin is an antioxidant that is thought to have a protective effect on neural cells, specifically in the brain. Vitamin D also influences calcium levels in the blood as well the immune system and the transport of electrical signals through the neurons.

The research is the first of its kind and sheds further light on the importance of vitamin D. The findings also open the door to further inquiry, especially in learning the exact mechanism behind vitamin D metabolism as well as the overall physiological effects of vitamin D deficiencies.

Vitamin D is also known as the sunshine vitamin because our bodies produce it when our skin is exposed to the sun. Fish is also a good source, while meat, cheese and eggs are to a lesser degree. For more information about vitamin D, visit the website for Office of Dietary Supplements.

If you have questions or concerns about Parkinson's disease, speak with your doctor or visit the website for the National Institute of Neurological Disorders and Stroke, a division of the National Institutes of Health (NIH).