A healthy brain depends on a healthy blood-brain barrier, a network of blood vessels that controls what substances can pass from the bloodstream into the brain.
Scientists from the University of Washington recently reviewed over 150 studies to better understand how changes in the blood-brain barrier may contribute to memory problems and brain health as we age.
Their findings suggest that even small leaks in this barrier could play a role in the mild memory decline often associated with aging and more serious conditions like Alzheimer’s disease.
The blood-brain barrier acts as a protective shield, preventing harmful substances in the blood from entering the brain. At the same time, it allows essential nutrients to pass through and removes waste products and toxins. This delicate balance is critical for maintaining brain health, but as people age, the blood-brain barrier becomes less effective.
In healthy aging, scientists observed small leaks in the blood-brain barrier. These minor leaks are linked to normal age-related forgetfulness, which is not considered harmful. However, in individuals who carry the ApoE4 gene—a strong genetic risk factor for Alzheimer’s disease—these leaks are more severe.
ApoE4 also makes it harder for the brain to clear amyloid beta-peptide, a protein that forms plaques commonly seen in Alzheimer’s disease. Even in normal aging, the blood-brain barrier becomes less efficient at clearing this protein, and the problem worsens in Alzheimer’s patients.
The study also highlighted two types of cells in the blood-brain barrier that change as people age: pericytes and astrocytes. Pericytes help maintain the barrier’s integrity, but their numbers decline with age, particularly in Alzheimer’s patients.
Astrocytes, on the other hand, become overactive, which may worsen the barrier’s leaks. Researchers believe that maintaining pericyte health could help slow age-related changes in the blood-brain barrier and support brain health.
Encouragingly, some lifestyle interventions known to promote healthy aging may also benefit the blood-brain barrier. Regular exercise, a calorie-controlled diet, and treatments like rapamycin have been shown to preserve pericyte health in animal studies.
These findings suggest that adopting healthy habits may protect the brain by keeping the blood-brain barrier functioning properly.
The blood-brain barrier’s importance extends beyond aging and Alzheimer’s. Its dysfunction has been linked to other diseases, such as multiple sclerosis and diabetes. As scientists continue to study this critical system, they hope to uncover more ways to prevent and treat brain-related illnesses.
This research underscores the importance of maintaining overall health as a way to support brain function. Simple lifestyle changes, like staying active and eating a balanced diet, may not only improve general well-being but also protect the brain from age-related decline.
The study, led by Dr. William Banks and published in Nature Aging, provides new insights into how we might preserve brain health as we grow older.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more information about brain health, please see recent studies about common exercises that could protect against cognitive decline, and results showing that this MIND diet may protect your cognitive function, prevent dementia.
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