A Canadian study has found a connection between poor kidney function and cognitive difficulties, including problems with reasoning, memory, and reaction time.
The research, led by neuropsychologist Dr. Shady Rahayel from Université de Montréal, highlights how the health of the kidneys can influence the brain. The findings were published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.
Chronic kidney disease (CKD) affects nearly 10% of the global population. When the kidneys don’t work properly, they fail to filter waste effectively from the blood, leading to a buildup of toxins.
This study suggests that kidney malfunction may also contribute to brain-related issues, even in people who have not been diagnosed with kidney disease.
Dr. Rahayel and his team analyzed data from approximately 16,000 healthy individuals to examine the relationship between the kidneys’ filtration capacity, known as the glomerular filtration rate (GFR), and cognitive performance.
The results showed that participants with lower GFR scores performed worse on cognitive tests, regardless of other factors like age, sex, education, or cardiovascular health. Brain scans also revealed shrinkage in the cerebral cortex, particularly in the frontal lobes—an area responsible for critical thinking and decision-making.
How Are the Kidneys and Brain Connected?
The exact mechanisms linking kidney function to brain health remain unclear. However, researchers believe several factors are involved.
One possibility is that when the kidneys fail to filter waste effectively, harmful substances build up in the bloodstream and affect the brain. This accumulation of toxins may contribute to neurodegeneration.
Another major factor is diabetes, the leading cause of chronic kidney disease. Diabetes can damage blood vessels, impacting both kidney and brain health.
However, the study found that the connection between poor kidney function and cognitive decline persisted even after accounting for vascular issues, suggesting additional underlying mechanisms.
Brain imaging from the study also showed signs of atrophy—thinning of the cerebral cortex—which is associated with neurodegenerative diseases like Alzheimer’s. “We measured the thickness of the cerebral cortex in 50,000 locations,” explained Dr. Rahayel.
“Even in individuals who had not yet developed kidney disease, we could see that kidney function was linked to brain atrophy.” This atrophy may explain why individuals with impaired kidney function are at higher risk for dementia and cognitive decline.
Implications and Next Steps
The findings highlight the importance of kidney health, not just for physical well-being but also for preserving cognitive function. The research suggests that early detection and management of kidney issues could play a role in preventing or delaying cognitive problems.
Dr. Rahayel emphasized the need for further research to pinpoint the specific brain regions most affected by kidney function and to understand the underlying biological pathways. This knowledge could pave the way for targeted treatments or interventions to protect brain health in people with kidney dysfunction.
What Can Be Done?
Maintaining good kidney health is crucial. Here are some steps that can help protect both kidney and brain function:
- Control Diabetes and Hypertension: Since these are major causes of kidney disease, managing blood sugar and blood pressure is key.
- Stay Hydrated: Drinking enough water supports kidney function and helps flush out waste.
- Adopt a Healthy Diet: A balanced diet low in salt, processed foods, and sugar can reduce strain on the kidneys and improve overall vascular health.
- Exercise Regularly: Physical activity supports heart and kidney health while promoting better blood flow to the brain.
- Monitor Kidney Health: Regular check-ups can help identify early signs of kidney problems.
This research underlines the deep connection between the kidneys and the brain, suggesting that better kidney health could also mean better cognitive health. Early intervention and healthy lifestyle choices may help reduce the risk of both kidney disease and cognitive decline, improving overall quality of life.
If you care about Alzheimer’s, please read studies about the likely cause of Alzheimer’s disease , and new non-drug treatment that could help prevent Alzheimer’s.
For more information about brain health, please see recent studies about diet that may help prevent Alzheimer’s, and results showing some dementia cases could be prevented by changing these 12 things.
The research findings can be found in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.
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