Vitamin D Supplementation Linked to Better Cognitive Test Performance in Older Adults: Preliminary Study

Taking a vitamin D supplement may help to preserve cognitive performance in adults that face an increased risk of developing dementia, according to a small observational study by Emory University researchers, with funding from the National Institute on Aging of the National Institutes of Health. The findings were published in Sleep Medicine.

Vitamin D deficiency has been associated with sleep problems like insomnia and more frequent nighttime awakenings, with implications related to cognitive function. In the preliminary study, researchers hypothesized that older adults with self-reported sleep problems who took high-dose vitamin D supplements would perform better on a cognitive assessment than similar counterparts who did not take a supplement.

In the present study, 54 adults with sleep disturbances and mild cognitive impairment (both considered dementia risks) were administered the Montreal Cognitive Assessment (MoCA). Participants who reported taking at least 5,000 IU vitamin D every day performed 13% better on measures of cognitive function compared to those who didn’t take a vitamin D supplement.

MoCA is a standard screening test designed to assess memory, thinking skills, and the risk of developing dementia. In contrast with the higher threshold, lower vitamin D dosages were not associated with improved cognitive scores.

“In older adults experiencing both sleep disturbance and mild cognitive impairment, this may represent a critical window for intervention, when cognitive changes are emerging, but opportunities to support brain health may remain,” said Victoria Pak, senior author and professor at Emory University’s Nell Hodgson Woodruff School of Nursing. “Identifying accessible and modifiable factors, such as vitamin D supplement intake, during the early stages of cognitive decline may become increasingly important, particularly as rates of Alzheimer’s disease continue to rise.” 

Notably, it didn’t seem to matter whether participants took vitamin D2 or D3 when it came to the impact on cognitive performance, the authors noted.