Accumulation of brain 'rust' is what Australian scientists have revealed to be the cause of Alzheimer's disease.
An imbalance in the metals needed for healthy brain function has been found at the root of the degenerative disease, which afflicts 10 per cent of people, aged over 60.
University of Melbourne Professor of Pathology Ashley Bush and his research colleagues have traced the imbalance to the brain's improper and related processing of zinc and iron.
The research focused on the complex relationship between amyloid precursor protein (APP) and its breakdown product amyloid, along with the zinc and iron.
Professor Bush said as zinc was seen to accumulate in amyloid it blocked the APP from performing its critical, and previously unknown, job of exporting iron out of the brain's neurons.
This led to a build-up of iron "in the grey matter", he said, resulting in oxidative stresses that could kill off neurons.
So the loss of mental function in an Alzheimer's patient is caused by rust in their brain
"That's the kind of chemistry that is going on in the brain and, similar to actual rust, it involves an abnormal combustion of oxygen with iron," the Courier Mail quoted Bush as saying.
"The brain is an unusual organ in that it has very high concentrations of metals which it uses for its electrical chemistry," he added.
The research will be published in the international journal Cell.