Why a lack of vitamin D can cause faster aging of the brain

A group of American researchers revealed that adults with high levels of this nutrient reduce the chances of suffering from a disease that affects memory by up to a third.

Spending more time in the sun may protect you against dementia, a study suggests. Exposure to sunlight causes the body to produce vitamin D, which has been linked to lower levels of inflammation and stronger bones in later life.

Now, a pioneering study has shown that people with high levels of this vitamin in the brain are 33% less likely to develop dementia.

In the latest work, the researchers examined brain tissue samples from 290 people from the Memory and Aging Rush Project, a long-term study of Alzheimer’s disease that began in 1997.

Vitamin D is an important regulator of calcium balance. In addition, it has important effects on the immune system

Participants’ cognition was assessed annually through a series of tests until their death, after which the volunteers donated their brains, spinal cords, and muscles.

The researchers also reviewed the results of her last cognitive assessment before she died. None of the participants had dementia when they entered the study, but by the time they died, 113 had been diagnosed, while 68 had mild cognitive impairment.

In addition, tissues from four brain regions were analyzed for vitamin D levels and signs of dementia. Two of the regions were associated with changes linked to Alzheimer’s, one with forms of dementia related to blood flow, and one region for which no association was known. The doctors conducting the analysis did not know which participants had dementia or cognitive impairment. Responses were compared with the final clinical assessment of cognition before death.

The results of the research, published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association, showed that people with higher levels of vitamin D in their brains were 25 to 33% less likely to be diagnosed with dementia. But these individuals were no less likely to have disease-related protein clusters in the brain.

These were amyloid plaques, Lewy bodies, or chronic or microscopic evidence of stroke. The scientists found that vitamin D was present in brain tissue, and that elevated levels of this substance in all four brain regions were correlated with better cognitive function.

However, brain vitamin D levels were not associated with any of the physiological markers associated with Alzheimer’s disease in the studied brain. These included amyloid plaque buildup, Lewy body disease, or evidence of chronic or microscopic strokes. This means that it is not yet clear how exactly vitamin D might affect brain function.

Dr Sarah Booth, a Rush University clinical nutritionist who led the research, said: “We now know that vitamin D is present in reasonable amounts in the human brain, and appears to be correlated with less decline in cognitive function. But we need to continue research to identify vitamin D-related brain neuropathology before we start designing future interventions.”

She added: “This research reinforces the importance of studying how diet and nutrients build resilience to protect the aging brain against diseases such as Alzheimer’s and other related dementias.”

Most people need about 600 international units (IU) of vitamin D per day, according to the US National Institutes of Health (NIH). But those over 70 need to eat up to 800 IU. This can be achieved by spending time outdoors or by eating a balanced diet with foods rich in vitamin D. A salmon fillet contains all the vitamin D you need for one day.

Can vitamin D protect against COVID-19?

Two and a half years after the COVID-19 pandemic was declared, new studies seek more evidence about the relationship between this nutrient and the prevention of SARS-CoV-2 infection. It is that vitamin D metabolites have long been known to promote the innate immune response against respiratory viruses and bacteria, which is why the nutrient was the center of attention for its possible role in the prevention and treatment of COVID -19.

Most of the studies published so far are observational and have shown conflicting results. Now, two new linked randomized studies have added much-needed evidence. According to work published in The BMJ (British Medical Journal), “the increase in vitamin D levels in adults during the SARS-CoV-2 pandemic was not associated with protection against respiratory tract infections or COVID-19 ″.

In publishing their conclusions, the authors noted that “among people with a high baseline prevalence of suboptimal vitamin D levels, vitamin D supplementation was not associated with a reduction in the risk of acute respiratory tract infection.” from all causes or COVID-19″.