Summary: Older people with cognitive decline who have higher levels of vitamin D in their brains had better cognitive function than their peers with lower levels of vitamin D.
Source: Tufts University
An estimated 55 million people worldwide are living with dementia, a number that is expected to increase as the world’s population ages. To find treatments that can slow or stop the disease, scientists need to better understand the factors that can cause dementia.
Researchers at Tufts University have completed the first study examining vitamin D levels 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.
The study was published on December 7 in Alzheimer’s and dementia: the journal of the Alzheimer’s Association.
“This research reinforces the importance of studying how foods and nutrients build resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias,” said Sarah Booth, lead author and correspondent, director of the Jean Mayer Center for Human Nutrition Research USDA. Aging (HNRCA) at Tufts and Principal Scientist of HNRCA’s Vitamin K Team.
Vitamin D supports many functions in the body, including immune responses and maintaining bone health. Food sources include fatty fish and fortified beverages (such as milk or orange juice); brief sun exposure also provides a dose of vitamin D.
“Many studies have implicated dietary or nutritional factors in performance or cognitive function in older adults, including many vitamin D studies, but all are based on dietary intakes or blood measurements of vitamin D” , said lead author Kyla Shea. Vitamin K team scientist and associate professor in the Friedman School of Nutrition Science and Policy at Tufts.
“We wanted to know if vitamin D is even present in the brain, and if so, how these concentrations relate to cognitive decline.”
Booth, Shea and their team examined brain tissue samples from 209 participants in the Rush Memory and Aging Project, a long-term study of Alzheimer’s disease that began in 1997. Rush University researchers assessed the participants’ cognitive function, older people with no signs of cognitive impairment, as they aged, and analyzed irregularities in their brain tissue after death.
In the Tufts study, researchers looked for vitamin D in four regions of the brain: two associated with Alzheimer’s disease-related changes, one associated with blood flow-related forms of dementia, and one region with no association. known to have cognitive decline related to Alzheimer’s disease. disease or vascular disease.
They found that vitamin D was indeed present in brain tissue and that high levels of vitamin D in all four brain regions were correlated with better cognitive function.
However, vitamin D levels in the brain were not associated with any of the physiological markers associated with Alzheimer’s disease in the brain studied, including amyloid plaque accumulation, Lewy body disease, or evidence of Alzheimer’s disease. chronic or microscopic cerebrovascular accidents. This means that it is still unclear exactly how vitamin D might affect brain function.
“Dementia is multifactorial, and many disease mechanisms underlying it have not been well characterized,” Shea says. “Vitamin D may be linked to outcomes that we have not yet examined, but plan to investigate in the future.”
Vitamin D is also known to vary between racial and ethnic populations, and most participants in the original Rush cohort were white. The researchers plan follow-up studies using a more diverse group of subjects to examine other brain changes associated with cognitive decline. They hope their work will lead to a better understanding of the role that vitamin D can play in the fight against dementia.
However, experts warn people not to use high doses of vitamin D supplements as a preventive measure. The recommended dose of vitamin D is 600 IU for people aged 1 to 70 and 800 IU for older people. Excess amounts can be harmful and have been linked to the risk of falling.
“We now know that vitamin D is present in reasonable amounts in the human brain, and it appears to be correlated with less decline in cognitive function,” Shea says. “But we need to do more research to identify the neuropathology to which vitamin D is linked in the brain before we start designing future interventions.”
Funding: The research reported in this article was supported by the National Institute on Aging of the National Institutes of Health under award numbers R01AG051641 and R01AG17917, as well as the Agricultural Research Service of the United States Department of Agriculture. Full information on authors, funders and conflicts of interest is available in the published article. The content is the sole responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the US Department of Agriculture.
About this vitamin D and cognitive research news
Author: Tara Combed
Source: Tufts University
Contact: Tara Pettinato – Tufts University
Image: Image is in public domain
Original research: Free access.
“Brain Forms of Vitamin D, Cognitive Decline, and Neuropathology in Community-Living Elderly” by Sarah Booth et al. Alzheimer’s and dementia
Brain forms of vitamin D, cognitive decline, and neuropathology in community-dwelling older adults
Vitamin D purportedly protects against cognitive decline and dementia based on observational data using circulating 25-hydroxyvitamin D (25(OH)D). Little is known about vitamin D in the human brain and its association with dementia or neuropathology.
Deceased from the Rush Memory and Aging Project (not = 290) had vitamin D concentrations measured in four brain regions. Associations with cognitive and neuropathological outcomes were estimated using linear and logistic regression.
The major form of vitamin D in all brain regions measured was 25(OH)D3. Upper brain 25(OH)D3 concentrations were associated with a 25% to 33% lower risk of dementia or mild cognitive impairment (MCI) at the last visit before death (all P ≤ .031). However, brain 25(OH)D concentrations were not associated with any studied postmortem neuropathological outcome.
Upper brain 25(OH)D3 concentrations were associated with better cognitive function before death. Further research is needed to clarify the specific mechanisms underlying this potentially protective relationship.
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