The aging kidney can harm the brain
Many studies point to a decline in kidney function as the cause of cognitive decline with age. Loss of kidney function is strongly correlated with dementia risk, for instance. The correlation is not a definitive indicator of aging. It is possible that any of the molecular damages that lead to aging or the intermediate effects of those damage can cause pathologies that are unrelated in other parts of the body. These pathologies are more common in those with higher levels of the damage.
There are still good reasons to believe that kidney failure, and its downstream effects, contribute to neurodegeneration. This may be primarily due to the degraded function of the blood vessel system. Vascular aging may cause brain damage through a variety of mechanisms. These include the damage caused by hypertension and the acceleration of atherosclerosis. Other causes are the failure to deliver enough nutrients and oxygen to an energy-hungry mind, or the disruption of the blood brain barrier that allows inflammatory cells and molecules to enter the brain.
The Interactions between Kidney Function and Cerebrovascular Disease. Vessel Pathology that Fires together Wires together.
Source:
https://www.fightaging.org/archives/2021/12/the-aging-kidney-harms-the-brain/
