Vitamin D is associated with your risk of developing dementia and Alzheimer’s disease. According to a new study, people who are Vitamin D deficient have a 51% increased risk of dementia while people who are severely Vitamin D deficient have a 122% increased risk.
The trans-Atlantic study was published yesterday in the leading journal Neurology. The group followed the Vitamin D levels of 1,658 elderly adults who, when the study began, had no signs of dementia. By monitoring Vitamin D levels and observing which adults developed dementia over the next two decades, the group discovered that people with Vitamin D deficiency more commonly developed dementia. This is known as a prospective trial.
The study defined Vitamin D deficiency as a blood Vitamin D level of less than 25-50 nmol/L; severe Vitamin D deficiency was less than 25 nmol/L. The Institute of Medicine recommends at least 50 nmol/L in a healthy diet, which can be kept simply by drinking milk and going outside–Vitamin D is made naturally in your skin when you’re in the sunlight.
How could Vitamin D decrease your risk of dementia? Perhaps by helping your brain cells get rid of pesky amyloid protein, before plaques form and cause damage, as suggested by other studies. Vitamin D also helps keep your veins and arteries healthy, reducing your risk for vascular dementia caused by stroke. But discovering precisely how Vitamin D protects you from dementia wasn’t the purpose of the Neurology study. Dr. David Llewellen, who headed the study, explains:
“We need to be cautious at this early stage and our latest results do not demonstrate that low vitamin D levels cause dementia. That said, our findings are very encouraging, and even if a small number of people could benefit, this would have enormous public health implications given the devastating and costly nature of dementia.”
While it is possible the association of Vitamin D with dementia was unique to this study, this is pretty unlikely because the study looked at such a large group that included white and African-American men and women. In addition, past studies had also shown a relationship between Vitamin D deficiency and dementia, albeit not as strong.
While no conclusive treatment for dementia or Alzheimer’s disease exists, knowing that Vitamin D deficiency is strongly associated with dementia paves the way for future research. Such studies could focus on whether certain foods like fish oil or Vitamin D supplements would be most helpful in preventing dementia.