Cognitive impairmentIntroduction

There is a growing body of literature reporting better brain function including better cognitive function with higher serum 25-hydroxyvitamin D [25(OH)D] levels. 

At the time of this review, we found ten journal papers reporting some degree of cognitive impairment at lower serum 25(OH)D levels.  A number of mechanisms have been suggested to explain the connection, including preservation of a healthy vascular system. 

Also, the vitamin D receptor and catalytic enzymes are colocalized in the areas of the brain involved in complex planning, processing, and the formation of new memories.

While dose-response levels have not been worked out yet, based on findings for other diseases, it is likely that maintaining serum 25(OH)D levels above 40 ng/mL will maintain good cognitive function. 

It remains to be seen whether increasing serum 25(OH)D levels for those with some cognitive impairment could reverse the condition, maintain the current condition, or have no effect.

Mild cognitive impairment (also known as incipient dementia, or isolated memory impairment) is a diagnosis given to individuals who have cognitive impairments beyond that expected for their age and education, but that do not interfere significantly with their daily activities1. It is considered to be the boundary or transitional stage between normal aging and dementia. 

There is a growing body of literature indicating that low serum 25(OH)D level is a risk factor for mild cognitive impairment.

Page last edited: 09 May 2011


  1. Petersen, R. C. Smith, G. E. Waring, S. C. Ivnik, R. J. Tangalos, E. G. Kokmen, E. Mild cognitive impairment: clinical characterization and outcome. Arch Neurol. 1999 Mar; 56 (3): 303-8.