Although they don’t yet know which came first, Parkinson’s disease or an insufficient store of vitamin D in the bloodstream, researchers at the Emory University School of Medicine have established a link between the two, a link strong enough to warrant further investigation.  The medical journal, Archives of Neurology, carries full details in its October issue.

The research team, led by Marian Evatt, MD, an Emory University assistant professor of neurology, explored the possibility that neurodegenerative diseases cause vitamin D insufficiency.  The team based its findings on the careful review of medical records, dating from 1992 to 2007, for 100 patients suffering from Parkinson’s disease, 100 with Alzheimer’s disease, and 100 elderly people with no sign of neurological disease.  One Alzheimer’s patient and one healthy patient were matched with each Parkinson’s patient for age and place of residence.

Some dietary supplements and a few foods contain vitamin D in substantial doses but the most abundant source of the vitamin is sunlight.  The human body produces vitamin D when UV-B radiation in sunlight touches the skin, a process that slows with age.  Vitamin D deficiencies are more common in darker, northern regions than in the sunnier south.  All patients in the Emory study lived in the Southeastern United States, where the days are warm and sunny.

Insufficient levels of vitamin D were discovered in as many as 55% of the Parkinson’s disease patients.  The other groups weren’t spared insufficiency either, with 41% of the Alzheimer’s patients and 36% of the healthy individuals measuring the vitamin in insufficient amounts.

Vitamin D deficiency, even more alarming than an insufficiency, was higher in the Parkinson’s patients than the other two groups, with 23% of the Parkinson’s group proving to be deficient, alongside 16% of the Alzheimer’s group and 10% of the healthy group.  While a deficiency is more serious than insufficiency, it is generally agreed that insufficiencies be treated to prevent deficiencies from developing.

Patients with Parkinson’s disease suffer severe mobility restrictions and may find it almost impossible to enjoy enough time in the sunshine to produce enough vitamin D to meet their body’s demands of the nutrient.  While it has long been understood that vitamin D is instrumental in forming and maintaining strong, healthy bones, medical research in recent years is showing the vitamin to be important for many other body functions, as well.

Recent studies have demonstrated how the nutrient produces peptides that keep the skin free of microbes, it helps regulate both blood pressure and insulin, and it is required to maintain a healthy nervous system.  There is also evidence that low levels of vitamin D increase the risk of various forms of cancer and autoimmune diseases that include diabetes and multiple sclerosis.

Parkinson’s disease targets nerve cells in the parts of the brain that utilize a chemical messenger, dopamine, to control movement, leaving a patient suffering from uncontrollable tremors, stiffness, and the ability to move only very slowly.  Oral dopamine is often prescribed to offset impaired function.

One part of the brain, the substantia nigra, is affected particularly hard by Parkinson’s disease.  It is also a part of the brain with a particularly high level of vitamin D receptors, leaving the Emory researchers to suggest vitamin D may be instrumental in the normal functioning of these particular brain cells.

An anonymous donor provided some of the funding for the Emory study, along with grants from the National Institute of Environmental Health Sciences, a part of the National Institutes of Health, the National Institute of Aging, and the National Center for Research Resources.

Source: Emory University