Alzheimer’s disease is a neurological disorder that progressively impacts memory and cognitive skills, often resulting in older patients struggling with simple everyday tasks. As symptoms worsen, people with Alzheimer’s often need support, frequently leaving the burden of care on family members.

Because over 7 million people live with Alzheimer’s and dementia in the U.S. alone and estimates project the number to almost double by 2050, researchers are trying to understand risk factors and what can be done to reduce those risks.

Emory University, Georgia, has now found an association between high doses of vitamin D and cognitive function in adults at increased risk of dementia. Their study, published in Sleep Medicine, found that taking 5,000 IU or more of vitamin D daily was linked to better cognitive performance among people with sleep disturbance and mild cognitive impairment (MCI).

“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,” said the study’s senior author Victoria Pak, associate professor at Emory University’s Nell Hodgson Woodruff School of Nursing, in a news release.

High Vitamin D Daily Intake Linked to Improved Cognitive Function

Since sleep disturbances and MCI can be early signs of dementia, the researchers invited 54 adults who were either diagnosed with or suspected of having those symptoms to participate in the study. The research team assessed participants’ cognition using the Montreal Cognitive Assessment (MoCA), a widely used screening tool to determine memory and thinking abilities.

Through self-reported questionnaires, the researchers collected information on participants’ vitamin D supplement intake. After statistical evaluation, the team observed an association between at least 5,000 IU of vitamin D daily and better cognitive function, even after adjusting for factors like age, sex, body mass index, and education.

“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,” added Pak, emphasizing the importance of timing in Alzheimer risk management.

Read More: 5 Recent Dementia Research Advances — From Blood Tests and Lithium to Lifestyle Changes

Vitamin D2 or D3 Made No Difference on Cognitive Function

Vitamin D is among the most common dietary supplements taken by adults in the U.S. It is an essential nutrient that supports many physiological functions, including bone, muscle, and nerve function.

The National Institutes of Health’s Office of Dietary Supplements explains that the daily amount of vitamin D depends on age and usually ranges from 400 IU in infants to 800 IU in adults 71 years and older. Although vitamin D is present in a few foods and can be produced in the skin through sun exposure, one in four people in the U.S. is deficient.

In the study, researchers noticed no significant cognitive differences between participants who took either vitamin D2 or D3, which are two different forms derived from plants or animal sources, respectively.

Vitamin D Deficiencies Are Linked to Sleep Disorders

The researchers describe how vitamin D may also influence sleep quality and sleep-wake cycles. Previous research shows that around 50 percent of people with moderate to severe Alzheimer’s disease are affected by sleep disturbances, suggesting that sleep deprivation and cognitive decline may influence each other.

Vitamin D’s impact on sleep disorders, like insomnia and increased nighttime awakenings, is already a focus of research. However, the research team notes that this preliminary study is the first to evaluate the relationship between vitamin D supplementation and global cognition in individuals with both sleep disturbance and MCI.

They emphasize that larger follow-up studies are necessary to confirm the results, including assessments of vitamin D toxicity, as current upper intake level recommendations are below 4,000 IU per day.

This article is not offering medical advice and should be used for informational purposes only.

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from a study published in Sleep Medicine:Vitamin D supplement intake is associated with better cognition in persons with sleep disturbance and mild cognitive impairment
• This article references information from The National Institutes of Health’s Office of Dietary Supplements: Vitamin D