Alzheimer’s disease may start in the gut and spread to the brain

By Alice Klein

A model of beta-amyloid

ALFRED PASIEKA / SCIENCE PHOTO LIBRARY

Alzheimer’s disease may be caused by the abnormal build-up of a protein in the gut that gradually spreads to the brain, according to research in mice.

In people with Alzheimer’s disease, a protein called beta-amyloid clumps together in the brain to form plaques that disrupt normal brain processes. Beta-amyloid deposits have also been found in the guts of people who died with the condition, but they have been largely overlooked.

John Rudd at the Chinese University of Hong Kong and his colleagues wondered if the beta-amyloid found in …