Older adults’ brains with higher levels of the nutrient function better, nutritionists say
Vitamin D pills could prevent Alzheimer’s disease, according to new research.
The brains of older adults with higher levels of the nutrient function better, according to nutritionists.
The main natural source is sunlight, but wrinkled skin is less efficient at processing it, meaning older adults are more likely to be deficient.
Corresponding author Dr Sarah Booth said: “This research reinforces the importance of studying how food and nutrients build resilience to protect the aging brain against diseases such as Alzheimer’s and other related dementias.”
The number of cases worldwide will triple to more than 150 million by 2050. And with no cure in sight, there is an increasing focus on preventative measures, such as lifestyle.
Dr. Booth and her colleagues examined postmortem brain tissue samples from 209 participants in the Rush Aging and Memory Project that began in 1997.
It is the first analysis of its kind and compares vitamin D levels in adults suffering from varying rates of cognitive decline.
Lead author Professor Kyla Shea explained: “Many studies have implicated dietary or nutritional factors in cognitive performance or function in older adults, including many studies on vitamin D, but all are based on dietary intake or levels in the blood of vitamin D”.
“We wanted to know if vitamin D is present in the brain, and if so, how these levels are related to cognitive decline.”
The team from Tufts University in Massachusetts found that a higher amount of vitamin D in the four regions studied was correlated with better mental abilities.
Two of the areas are associated with Alzheimer’s disease-related changes, one with dementias due to blood flow, and the other is not associated with brain or vascular diseases. Participants’ cognitive function was assessed initially and as they aged; irregularities in brain tissue were identified after death. No relationship was found between vitamin D levels and any of the physiological markers associated with Alzheimer’s disease. These include rogue amyloid beta proteins that accumulate in plaques, Lewy body dementia, or chronic or microscopic strokes. The analysis means that exactly how vitamin D might affect brain function is still unclear.
Professor Shea said: “Dementia is multifactorial and many of the underlying pathological mechanisms have not been well characterized.”
“Vitamin D could be related to outcomes that we have not yet analyzed, but that we plan to study in the future.”
Vitamin D is also known to vary between racial and ethnic populations, and most participants in the original 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 will lead to a better understanding of the role vitamin D can play in warding off dementia.
Experts caution people against taking large doses of vitamin D supplements as a preventative measure. The recommended dose of vitamin D is 600 IU (international units) for children under 70 years of age and 800 for adults. Excessive amounts can cause harm and have been linked to a risk of falls.
Professor Shea said: “We now know that vitamin D is present in reasonable amounts in the human brain and appears to be associated with less decline in cognitive function.”