THE ESSENTIAL
- Alzheimer’s disease is the most common form of neurodegenerative disease. In France, more than 900,000 people are affected, mostly women.
- Only 1 in 2 dementias is diagnosed, all stages combined (only one in 3 cases in the mild stages).
- The number of new cases is estimated at more than 225,000 per year. By 2050, the number of people affected by a neurocognitive disease should reach more than 1,800,000 cases (9.6% of those over 65).
Could vitamin D be a key in the fight against Alzheimer’s disease? Maybe so, according to new US research. This essential vitamin for our health is synthesized through exposure to sunlight. But as you age, the skin becomes less efficient at converting it. Older people are therefore more likely to be deficient.
A new studyconducted by Tufts University and published in the journal Alzheimer’s & Dementiashows how effective vitamin D is in improving cognitive health.
A high level of vitamin D linked to better cognitive function
Dr. Booth and her colleagues examined postmortem 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. At the time, scientists from Rush University, located in Chicago in the United States, evaluated the cognitive function of participants (elderly people without any signs of cognitive impairment) as they aged, and analyzed irregularities in their brain tissue after their dead.
In the Tufts University study, the researchers looked for vitamin D in four regions of the brain: two associated with changes linked to Alzheimer’s disease, one associated with forms of dementia linked to blood circulation and an area with no known association with cognitive decline related to Alzheimer’s 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.
Alzheimer’s: We don’t yet know how vitamin D affects the brain
However, vitamin D levels in the brain were not associated with any of the physiological markers linked to Alzheimer’s disease in the brains 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.
“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 functions”said one of the main authors of the study, Kyla Shea, in a communiqué. “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.”continues the professor at Tufts University.
The study authors emphasize how multifactorial dementia is, with mechanisms that are not yet well enough understood. However, according to them, vitamin D could have a significant role, which is why it is necessary to better study this subject in the future. “This research reinforces the importance of studying how foods and nutrients create resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias”added Dr. Sarah Booth, another of the authors of the study.