Vitamin D for cognitive decline and Parkinson's Disease

Two studies have just been published linking Vitamin D status to brain health. The authors of one paper appearing in Archives of Internal Medicine observe:

"To our knowledge, no prospective study has examined the association between vitamin D and cognitive decline or dementia."

They examined the correlation between low levels of serum 25-hydroxyvitamin D (25[OH]D) and the risk of serious loss of cognitive function in 858 adults over 8 years. What did the data show?

"...substantial cognitive decline on the MMSE [Mini-Mental State Examination] in participants who were severely serum 25(OH)D deficient (levels <25 nmol/L) in comparison with those with sufficient levels of 25(OH)D (≥75 nmol/L)...the scores of participants who were severely 25(OH)D deficient declined by an additional 0.3 MMSE points per year more than those with sufficient levels of 25(OH)D."

Thus their conclusion:

"Low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied over a 6-year period, which raises important new possibilities for treatment and prevention."

The same week a study was published in Archives of Neurology that examines the relation between Vitamin D and Parkinson Disease. The authors set out to:

"...investigate whether serum vitamin D level predicts the risk of Parkinson disease."

They crunched the numbers for 3,173 men and women who were followed up over 29 years (the baseline serum 25-hydroxyvitamin D level was determined from frozen samples) for the relationship between serum vitamin D concentration and Parkinson disease. The data showed that:

"Individuals with higher serum vitamin D concentrations showed a reduced risk of Parkinson disease. The relative risk between the highest and lowest quartiles was 0.33 [about a third less] after adjustment for sex, age, marital status, education, alcohol consumption, leisure-time physical activity, smoking, body mass index, and month of blood draw."

Thus their conclusion:

"The results are consistent with the suggestion that high vitamin D status provides protection against Parkinson disease."

The results of these studies are not surprising considering that Vitamin D is necessary for regulating the immune inflammatory response and both dementia and Parkinson's involve chronic brain inflammation. By the way, as stated in Science Insider:

"Most Alzheimer's disease (AD) researchers agree that the disease starts ravaging the brain years, if not decades, before the first symptoms of forgetfulness appear."

New diagnostic criteria were just proposed at the International Conference on Alzheimer's Disease in Honolulu.