Vitamin D Deficiency Doubles the Risk of Alzheimer Disease

In this landmark study, blood levels of vitamin D were measured in 1658 elderly adults who were free from dementia or heart disease. Follow up more than five years later revealed that those with vitamin D deficiency (defined as 25-50 nmol/L) were over 50% more likely to have dementia (cognitive impairment that is milder than Alzheimers) and 70% more likely to have Alzheimers. When vitamin D levels fell below 25 nmol/L, which is what the authors called severe deficiency, the risk of dementia and Alzheimers rose even more to 125% and 122% respectively, meaning they are more than twice as likely to experience major cognitive dysfunction as they age when vitamin D levels are low.

In an unrelated but similar study, people over 70 were assessed for mild cognitive impairment and vitamin D levels. In this population, it was found that lower vitamin D correlated with cognitive decline, even in those without dementia. Although the mechanism of action for the protective role of vitamin D is still not totally clear, a new paper sheds some light on how this vitamin protects the brain, citing a anti-inflammatory role for vitamin D in pericytes, which are specialized brain cells that protect the blood-brain barrier.

(Neurology, August 2014)
(Dementia and Geriatric Cognitive Disorders, June 2014)
(Journal of Alzheimer Disease, June 2014)

http://www.spectracell.com/volume-2014-issue-no-8-august/ Web. 03 September. 2014.