In a recent study of seniors ages 65-99, only 35 percent had sufficient vitamin D blood levels. Those with higher levels of Vitamin D had better cognitive performance on the tests than those in the deficient and insufficient categories, particularly on measures of “executive performance,” such as cognitive flexibility, perceptual complexity, and reasoning.
Metabolic pathways for vitamin D have been found in the hippocampus and cerebellum areas of the brain involved in planning, processing, and forming new memories. This suggests that vitamin D may be implicated in cognitive processes
The 2009 study appears in the Journals of Gerontology, Series A, Biological Sciences and Medical Sciences.