In an excellent paper, a pair of researchers (father and son) presented considerable evidence that vitamin D deficiency is a cause, and possibly the major cause, of Parkinson's disease. The researchers reviewed a 1997 case report in which a patient with Parkinson's disease steadily improved when treated daily with 4,000 IU of vitamin D. At the same time, two new meta-analysis studies (which combine data from multiple reports) have found even more evidence that vitamin D is an important cancer-fighting tool. The first study examined nearly 1,800 records and found that: People with the highest blood levels of vitamin D had the lowest risk of breast cancer Those with the lowest vitamin D levels had the highest rates of breast cancer The second study, which looked at nearly 1,500 people, showed similar results. Raising vitamin D levels (serum level of 25-hydroxyvitamin D) to 34 ng/ml reduced rates of colorectal cancer by half, while raising levels to 46ng/ml cut the risk by two-thirds. Movement Disorders January 17, 2007 Science Daily February 8, 2007