Key Points:
- Researchers found high vitamin D levels in four regions of the brain correlated with better cognitive function.
- But, the levels of vitamin D didn’t associate with any of the physiological markers normally seen with Alzheimer’s disease.
- The researchers are planning follow-up studies using a more diverse group of subjects to look at other brain changes for a clearer picture.
Researchers at Tufts University have completed the first study examining levels of vitamin D in brain tissue, specifically in adults who suffered from varying rates of cognitive decline. They found that members of this group with higher levels of vitamin D in their brains had better cognitive function.
In their study, published in Alzheimer’s & Dementia, researchers examined samples of brain tissue from 209 participants in the Rush Memory and Aging Project, a long-term study of Alzheimer’s disease that began in 1997. The Tufts researchers looked for vitamin D in four regions of the brain samples—two associated with changes linked to Alzheimer’s disease, one associated with forms of dementia linked to blood flow, and one region without any known associations with cognitive decline related to Alzheimer’s disease or vascular disease. They found that vitamin D was indeed present in brain tissue, and high vitamin D levels in all four regions of the brain correlated with better cognitive function.
However, the levels of vitamin D in the brain didn’t associate with any of the physiological markers associated with Alzheimer’s disease in the brain studied, including amyloid plaque buildup, Lewy body disease, or evidence of chronic or microscopic strokes. This means it’s still unclear exactly how vitamin D might affect brain function.
“Dementia is multifactorial, and lots of the pathological mechanisms underlying it have not been well characterized,” said lead author Kyla Shea, associate professor at the Friedman School of Nutrition Science and Policy at Tufts. “Vitamin D could be related to outcomes that we didn’t look at yet, but plan to study in the future.”
Vitamin D is also known to vary between racial and ethnic populations, and most of the participants in the original Rush cohort were white. The researchers are planning follow-up studies using a more diverse group of subjects to look at other brain changes associated with cognitive decline. They hope their work leads to a better understanding of the role vitamin D may play in staving off dementia.
“This research reinforces the importance of studying how food and nutrients create resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias,” said senior and corresponding author Sarah Booth, director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts.