Medical News

27.10.08: Lack Of Vitamin D Linked To Parkinson’s Disease

A majority of Parkinson’s disease patients had insufficient levels of vitamin D in a new study from Emory University School of Medicine.

Most Americans get the majority of their vitamin D from exposure to sunlight or by dietary supplements; fortified foods such as milk and packaged cereals are a minor source. Only a few foods in nature contain substantial amounts of vitamin D, such as salmon and tuna.

The body’s ability to produce vitamin D using UV-B radiation from the sun decreases with age, making older individuals at increased risk of vitamin D deficiency. “We found that vitamin D insufficiency may have a unique association with Parkinson’s, which is intriguing and warrants further investigation,” doctors say. The connection could come partly because patients with Parkinson’s have mobility problems and are seldom exposed to the sun, or because low vitamin D levels are in some way related to the genesis or progression of the disease.

Specialists say they saw their results as striking because their study group came from the Southeast, not a region with long gloomy winters, where vitamin D insufficiency is thought to be more of a problem. Doctors have known for decades that vitamin D plays a role in bone formation, scientists say. More recently, scientists have been uncovering its effects elsewhere, including producing peptides that fight microbes in the skin, regulating blood pressure and insulin levels, and maintaining the nervous system.

Low vitamin D levels also appear to increase the risk of several cancers and auto-immune diseases such as multiple sclerosis and diabetes. Parkinson’s disease affects nerve cells in several parts of the brain, particularly those that use the chemical messenger dopamine to control movement. The most common symptoms are tremor, stiffness and slowness of movement. These can be treated with oral replacement of dopamine.

Previous studies have shown that the part of the brain affected most by Parkinson’s, the substantia nigra, has high levels of the vitamin D receptor, which suggests vitamin D may be important for normal functions of these cells. Emory clinicians are conducting further research to investigate whether vitamin D insufficiency is a cause or possibly a result of having Parkinson’s. In a pilot study, Parkinson’s patients are receiving either standard or larger doses of vitamin D, with an eye towards possibly reducing the severity of their condition.