The cause of Alzheimer’s is not just in the brain.

Alzheimer’s disease could be a problem that involves the whole body, according to new research.

Alzheimer’s — the most common form of dementia — has usually been thought of as only a brain disease.

However, research now suggests the disease could be triggered elsewhere in the body.

Chinese research has shown that amyloid-beta — the protein thought central to Alzheimer’s — can contribute to the disease even when it comes from outside the brain.

The findings suggest drugs that might be able to target the kidney or liver to try and reduce toxic proteins before they reach the brain.

Professor Weihong Song, who led the research, said:

“The blood-brain barrier weakens as we age.

That might allow more amyloid beta to infiltrate the brain, supplementing what is produced by the brain itself and accelerating the deterioration.”

It is already known that the toxic amyloid-beta protein linked to Alzheimer’s is produced in the blood platelets, blood vessels and muscles.

Until now it was unclear whether it could pass into the brain.

Professor Song thinks the protein could be biochemically tagged to allow the liver or kidneys to clear it.

Professor Song added:

“Alzheimer’s disease is clearly a disease of the brain, but we need to pay attention to the whole body to understand where it comes from, and how to stop it.”

The study was published in the journal Molecular Psychiatry (Bu et al., 2017).