Your brain has a special protective system called the blood-brain barrier. This barrier is made up of blood vessels that act like a security gate, carefully deciding what can pass from your blood into your brain.
It allows in important nutrients and keeps out harmful substances. It also helps remove waste from the brain. When this barrier works well, it helps keep your brain healthy.
But scientists at the University of Washington have found that as we age, this barrier can start to weaken and leak. They reviewed more than 150 studies to better understand how these changes might affect memory and brain health.
Their research shows that even tiny leaks in the barrier can be linked to memory problems and could lead to more serious conditions like Alzheimer’s disease.
In normal aging, small leaks in the blood-brain barrier may cause mild forgetfulness. This is not unusual and is not considered dangerous. But for people who carry a gene called ApoE4, the leaks tend to be worse.
This gene is known to increase the risk of Alzheimer’s disease. ApoE4 also makes it harder for the brain to get rid of a harmful protein called amyloid beta-peptide. This protein can build up in the brain and form sticky clumps called plaques, which are a hallmark of Alzheimer’s.
As we get older, the blood-brain barrier becomes less effective at removing this protein. This problem is even more severe in people with Alzheimer’s. The researchers also found that two important types of brain cells—called pericytes and astrocytes—change with age and affect how well the barrier works.
Pericytes help keep the blood-brain barrier strong. But as people age, especially those with Alzheimer’s, the number of pericytes goes down. This weakens the barrier and makes it easier for harmful substances to get into the brain.
Astrocytes are another kind of brain cell that support the barrier. As we get older, these cells can become overactive. When that happens, they may make the leaks in the barrier worse.
The good news is that healthy lifestyle habits may help protect the blood-brain barrier. In animal studies, regular exercise, eating fewer calories, and certain treatments like rapamycin helped keep pericytes healthy. This suggests that simple changes in daily life could help protect the brain and slow down memory decline.
The blood-brain barrier is important not just for aging and Alzheimer’s, but also for other diseases like multiple sclerosis and diabetes. Scientists are still learning about how it works and how to fix it when things go wrong. But what we know so far suggests that keeping the barrier healthy is key to protecting brain function as we get older.
This research, led by Dr. William Banks and published in the journal Nature Aging, reminds us that taking care of our overall health—by staying active and eating well—may also help us keep our brains strong as we age.
If you care about dementia, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
For more health information, please see recent studies what you eat together may affect your dementia risk, and time-restricted eating: a simple way to fight aging and cancer.
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