Study is the first to examine calciferol in brain tissue, which may help investigators understand dementia and its causes.
Individuals with higher levels of vitamin D in their brains who also suffered from varying degrees of cognitive decline, had better cognitive function, according to the results of a study published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
“Many studies have implicated dietary or nutritional factors in cognitive performance or function in older adults, including many studies of vitamin D, but all of them are based on either dietary intakes or blood measures of vitamin D,” Kyla Shea, PhD, an associate professor at the Friedman School of Nutrition Science and Policy at Tufts University, said in a statement. “We wanted to know if vitamin D is even present in the brain, and if it is, how those concentrations are linked to cognitive decline.”
Vitamin D has been known to support functions in the body, including immune responses and maintaining healthy bones. Fatty fish and fortified beverages, such as milk and orange juice, are good sources of vitamin D, as as brief exposure to sunlight.
Investigators used samples of brain tissue from 209 individuals in the Rush Memory and Aging Project, a long-term study of Alzheimer disease (AD) that began in 1997.
They looked for vitamin D in 4 regions of the brain: 2 being associated with changes linked to AD, 1 associated with dementia linked to blood flow, and 1 without any known association with cognitive decline related to AD or vascular disease.
Vitamin D was present in brain tissue, and high vitamin D levels in all 4 regions of the brain correlated with better cognitive function, according to the results.
However, investigators also found that the levels of vitamin D in the brain are not associated with any physiological markers associated with AD, including amyloid plaque buildup, evidence of chronic or microscopic strokes, or Lewy body disease.
“Dementia is multifactorial, and lots of the pathological mechanisms underlying it have not been well characterized,” Shea said. “Vitamin D could be related to outcomes that we didn’t look at yet but plan to study in the future.”
Investigators are planning follow-up studies using more diverse individuals, because vitamin D is known to vary between ethnic and racial populations. They plan to look at other brain changes that are associated with cognitive decline and hope the results will lead to a better understanding of vitamin D’s association with dementia.
Furthermore, they also caution individuals not to use large doses of vitamin D supplements as a preventative measure, because that can cause harm and have been linked to the risk of falling.
“We now know that vitamin D is present in reasonable amounts in human brains, and it seems to be correlated with less decline in cognitive function,” Shea said. “But we need to do more research to identify the neuropathology that vitamin D is linked to in the brain before we start designing future interventions.”
Researchers find that brains with more vitamin D function better. EurekAlert. News release. December 7, 2022. Accessed January 11, 2023. https://www.eurekalert.org/news-releases/973266