For older adults already showing early signs of cognitive trouble, one supplement stood out in a small new study.
Research from Emory University found that adults with mild cognitive impairment and sleep disturbances who took at least 5,000 IU of vitamin D a day scored more than 13 percent higher on a cognitive test than participants who took none.
The findings were published in Sleep Medicine.
The study included 54 adults with sleep disturbances and mild cognitive impairment, or MCI, both of which can be associated with the early stages of dementia.
Researchers found the higher-dose vitamin D group performed better on the Montreal Cognitive Assessment, or MoCA, even after adjusting for other factors. The test is used to assess memory, thinking skills and dementia risk.
Lower daily doses of vitamin D were not associated with improved cognitive scores.
The researchers said timing may matter. MCI is an intermediate stage between normal cognitive aging and dementia.
“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,” says Victoria Pak, senior author of the study.
“Identifying accessible and modifiable factors, such as vitamin D supplement intake, during the earlier stages of cognitive decline may become increasingly important, particularly as rates of Alzheimer’s disease continue to rise,” adds Pak, associate professor at Emory University’s Nell Hodgson Woodruff School of Nursing.
The researchers also looked at the form of vitamin D. Cognitive performance was similar among people taking vitamin D2 and those taking vitamin D3.
The study says vitamin D is involved in muscle and nerve function and also plays a role in sleep quality and sleep-wake cycles.
Sleep problems are common among people with Alzheimer’s disease. The study says 50 percent of people with moderate to severe Alzheimer’s disease report sleep disturbances.
The researchers said vitamin D deficiency has previously been associated with sleep problems including insomnia and more frequent nighttime awakenings.
The study was funded by the National Institute on Aging of the National Institutes of Health, R01AG097853-01 and R61AG080606.
Other Emory co-authors were Sirui Zhou, Paul Sudeshna, Lynn Marie Trotti and Donald Bliwise.
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