Vitamin D Deficiency and Parkinson’s or Alzheimer’s Disease
These conclusions added weight to the discovery that low intakes of vitamin D may be associated with Parkinson's disease. Other studies have shown that the part of the brain which is most affected by Parkinson's disease has high levels of the vitamin D receptor, suggesting than vitamin D is necessary for these cells to function properly.
The study also compared the results with patients suffering from Alzheimer's disease. It found that 41% of Alzheimer's sufferers had a deficiency of vitamin D, but this was lower than the percentage of Parkinson's sufferers that lacked vitamin D.
Most Americans get their daily requirements of vitamin D from exposure to sunlight or through dietary supplements. As people age, their body is less able to produce vitamin D from the sun, and although some foods such as cereals are enriched with this essential vitamin, few other foods met the daily requirements. Milk and dairy products were a minor contributing source, but salmon and tuna had the highest concentrations. As the body cannot store vitamin D, the only way to ensure a sufficient dose was by taking a supplement.
The link between a deficiency in vitamin D and Parkinson's disease needs to be further investigated. One point already raised is that Parkinson's sufferers are less mobile and are therefore less exposed to natural sunlight, possibly causing the deficiency, not caused by it. Regionally, the lack of vitamin D also needs to be investigated, as those in sunnier states should have a lower risk of a deficiency than those living in states which have a long, dark winter. The study concentrated on those living in southeast America where sunshine hours were generally high.
All medical experts agree that any deficiency in vitamin D should be treated, as a deficiency appears to increase the risk of autoimmune and cardiovascular disorders. The vitamin is known to play an important role in bone formation at all ages. Insufficiency of vitamin D is deemed to be less than 20 nanograms per milliliter of blood.