As the world's population ages, the estimated 55 million people who already have dementia are likely to increase. The Alzheimer's Association estimates that there are 6.5 million Alzheimer's patients living in the United States alone. Researchers require a better understanding of the elements that can cause dementia in order to develop treatments that can either slow or stop the disease.
The first investigation on vitamin D levels in brain tissue, specifically in adults who had various rates of cognitive loss, has been completed by researchers at Tufts University. They found that those in this group had greater cognitive performance and higher amounts of vitamin D in their brains. 

On December 7, the research was published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association. Numerous bodily processes, including immunological responses and maintaining strong bones, are supported by vitamin D. In addition to fortified foods (such milk or orange juice) and fatty fish, vitamin D can also be obtained by brief sun exposure. 

D. Rush University researchers evaluated the subjects' cognitive ability as they aged—older adults who showed no evidence of cognitive impairment—and looked for anomalies in their brain tissue after death. 

In the Tufts study, scientists searched for vitamin D in four areas of the brain: two connected to alterations linked to Alzheimer's disease, one connected to dementia types linked to blood flow, and one region without any known connections to cognitive decline connected to vascular disease or Alzheimer's disease.