Low levels of vitamin D linked to Parkinson's

Oct 14 2008

Scientists in the U.S. have found that many people suffering from Parkinson's disease have inadequate levels of vitamin D compared to healthy people.

The team at Emory University in Atlanta are now testing whether vitamin D supplements can in fact ease the symptoms of Parkinson's disease.

The researchers found that out of a group of elderly people, 100 with Parkinson's disease, 97 with Alzheimer's disease and 99 healthy individuals matched for age, sex, race, genotype and geographic location, 55% of Parkinson's patients had insufficient levels of vitamin D, compared to 36% of healthy elderly people.

Dr. Marian L. Evatt and her colleagues say the average vitamin D concentration in the group with Parkinson's disease was considerably lower than the Alzheimer's disease and the healthy group - however it is unclear as yet if the vitamin deficiency is a cause or the result of Parkinson's.

Parkinson's disease is a progressive disease which 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 and these are commonly treated with the oral replacement of dopamine.

The researchers say vitamin D is important for maintaining many physiologic functions and vitamin D deficiency is associated with increased risk of disease.

They say patients with chronic neurodegenerative diseases frequently have many risk factors for vitamin D insufficiency, including advancing age, obesity, avoidance of sun exposure, residence in northerly latitudes and having darker skin.

Previous research indicates that the part of the brain most affected 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.

While vitamin D can be found in oily fish such as tuna, mackerel and sardines as well as in milk, by far the best source is the exposure of the skin to sunlight.

As the body ages, it's ability to produce the vitamin decreases, making older people more prone to deficiency and there is a theory that this is exacerbated in people with Parkinson's because their condition limits the amount of time they spend out of doors.

But some scientists suspect that low vitamin D levels are in some way related to the genesis and origin of the disease.

The researchers say their findings were interesting because the study group came from the South West of the U.S. which has plenty of sunshine - they say this is intriguing and warrants further investigation.

Experts say research is required to determine at what stage the deficiency in vitamin levels occurs in the brains of people with Parkinson's and whether the provision of a dietary supplement, or increased exposure to sunlight may help alleviate symptoms or have an affect on the rate of the condition's progression.

The medical profession have been aware of the role of vitamin D in bone formation for decades but now scientists have revealed its effects elsewhere, including producing peptides that fight microbes in the skin, regulating blood pressure and insulin levels, and maintaining the nervous system.

The researchers say finding a high incidence of vitamin D deficiency in the Parkinson's patients highlights the importance of routinely checking the level of the vitamin in elderly patients, especially as a deficiency is strongly linked with a higher incidence of osteoporosis, falls and hip fractures and has also been associated with a higher incidence of several forms of cancer and autoimmune disorders.

Low vitamin D levels also appear to increase the risk of diabetes.

The study appears in the journal Archives of Neurology.