High-Dose Vitamin D Linked to Better Cognitive Scores in At-Risk Older Adults

Emory University researchers studied 54 adults with both sleep disturbances and mild cognitive impairment (MCI), an intermediate stage between normal aging and dementia — conditions that can appear in the early stages of dementia. The findings were published in Sleep Medicine.

Participants who took at least 5,000 IU of vitamin D daily scored more than 13% higher on the Montreal Cognitive Assessment (MoCA), a widely used screening test for memory, thinking skills and dementia risk, than participants who took none, even after adjusting for other factors. Lower daily doses of vitamin D were not associated with improved scores.

Vitamin D2, typically obtained from plants or fungi, and vitamin D3, which the body produces after sun exposure or gets from animal foods, showed similar results. Senior author Victoria Pak, associate professor at Emory's Nell Hodgson Woodruff School of Nursing, said this stage, when both sleep and cognitive changes are emerging, may represent "a critical window for intervention."

The researchers describe the study as preliminary, and say it is the first to examine vitamin D supplement intake specifically in a group with both mild cognitive impairment and sleep disturbances. More than 7 million Americans currently live with Alzheimer's dementia, a number estimated to reach nearly 13 million by 2050, and about half of people with moderate to severe Alzheimer's report sleep disturbances.