Low vitamin D levels Linked to Parkinson’s Disease

Researchers took blood samples from 3,000 people between 1978 and 1980, then followed them for 30 years. They found that people with the lowest levels of vitamin D were three times more likely to develop Parkinson's disease in that time than people with the highest levels.

Parkinson's disease is a degenerative brain and nervous condition that produces impairment of speech and movement dysfunction. Researchers do not know how vitamin D might affect the development of the disease, but they have suggested that it might help protect the body's nerve cells from damage.

"Further research is required to find out whether taking a dietary supplement, or increased exposure to sunlight, may have an effect on Parkinson's, and at what stage these would be most beneficial," said Kieran Breen, director of research at Parkinson's UK.

Vitamin D, which is produced in the skin upon exposure to sunlight, has long been known to play an essential role in the formation and maintenance of teeth and bones. Newer research suggests that it also plays a critical role in regulating immune function, thereby protecting against infection, cancer, autoimmune disorders and even chronic conditions such as heart disease or Alzheimer's.

These new findings have called into question whether recommendations for vitamin D intake have been set too low.

"At this point, 30 nanograms per milliliter of blood or more appears optimal for bone health in humans," wrote Marian Evatt of Emory University in an editorial accompanying the Finnish study. "However, researchers don't yet know what level is optimal for brain health or at what point vitamin D becomes toxic for humans, and this is a topic that deserves close examination."