Vitamin D deficiency is a major cause of dementia and it even causes physical abnormalities in the brain. People who are deficient experience a rate of cognitive decline that is three times faster than someone with adequate levels of the vitamin.
People should start supplementing and getting out into the sunshine more often once they reach the age of 60, say researchers from Rutgers University.
The researchers checked the levels of the vitamin in a group of 382 racially-diverse men and women with an average age of 75, and observed their cognitive functions over a five-year period.
All of the participants were deficient in the vitamin, or had an insufficiency. During the five years, those who were deficient experienced cognitive decline that was two to three times faster than those who were insufficient.
In other words, they started to lose cognitive function within two years of starting the trial.
(Source: JAMA Neurology, 2015; doi: 10.1001/jamaneurol.2015.2115)