A healthy lifestyle builds a “cognitive reserve” in the brain that can prevent dementia

New research suggests that a healthy lifestyle may help prevent dementia, perhaps by creating a resilient “cognitive reserve” in the aging brain.

The study was based on brain autopsies of 586 people who lived to an average age of almost 91 years. The researchers compared each person’s late-life lifestyle and mental abilities to their neurological signs of dementia, such as brain protein plaques or brain changes. blood flow.

None of these brain factors appear to greatly affect the positive link between a healthy lifestyle and a person’s mental abilities at the end of life, said a team led by Dr. Klodian Dhana of Rush University Medical Center from Chicago.

This means that a good diet, regular physical activity and other factors can instead “provide a cognitive reserve” that buffers negative changes occurring in the brain, allowing older adults to “maintain their cognitive abilities” as they age. time, the researchers said.

“You can almost cheat the biology a little bit and not feel the symptoms as early” as a less healthy person, said Dr. Liron Sinvani, who was not involved in the study. She directs geriatric inpatient services at Northwell Health in Uniondale, New York.

The study was published February 5 in the journal JAMA Neurology.

As Dhana’s group notes, it has long been known that certain lifestyle choices — eating well, exercising, avoiding smoking and drinking too much — are linked to lower rates of dementia.

But how does a healthy lifestyle work its neurological magic?

To find out, they used data from the ongoing Rush Memory and Aging project. Over a 24-year period, the project tracked the late-life lifestyle and mental functions of 586 participants, all of whom had died and donated their brains for autopsy.

The group lived a long time, with an average of just under 91 years. Seventy-one percent were women.

Dhana’s group conducted brain autopsies focusing on the classic neurological signs of dementia: a buildup of amyloid protein plaques and tangles in brain tissue, as well as changes in the brain’s vasculature (circulatory system) that could indicate a reduction in blood flow caused by events. like strokes or mini-strokes.

As expected, they found that people who had lived very healthy lives were much more likely to retain their intelligence as they approached the end of their lives. Each one-point increase in a person’s “lifestyle score” was associated with an increase in their “overall cognitive score” at the end of life, the researchers found.

However, most of this relationship had little correlation with the brain changes observed in autopsies.

In other words, even though protein plaques, tangles, or vascular system disorders might appear in the brain of a deceased person who had lived a healthy life, that person’s mental scores remained high.

The only (very slight) effect was observed regarding the accumulation of amyloid plaques in the brain. Dhana’s group calculated that amyloid plaque reduction could account for 11.6% of the lifestyle/cognition relationship.

All of this reinforces the idea that a healthy lifestyle provides the aging brain with a kind of “reserve,” allowing it to function well even when changes that typically signal dementia are taking place.

So, “if you take two people and they both have the same amount of this bad protein in their brain, the person who has the healthier lifestyle may have better cognitive function,” Sinvani explained, who is also a professor of medicine. at the Zucker School of Medicine at Hofstra/Northwell.

“You can function at a higher level, function normally, function without impairment for longer,” she said.

When it comes to exercise, Sinvani believes the study also shows that you’re “never too old or too frail to start improving your lifestyle.”

Current exercise recommendations call for at least 150 minutes of physical activity per week. For seniors who have been inactive for a long time, Sinvani suggests consulting a doctor and/or personal trainer before embarking on a workout program.

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