Scientists of the University of Rochester discovered copper damages a protein called LRP that transports a substance called amyloid beta from the brain. Amyloid beta accumulates in the brains of people with Alzheimer's.

Although metals have long been thought to contribute to Alzheimer's, the researchers said their discovery marks the first time a mechanism for a specific metal's role in the disease has been identified.

The study was conducted in mice, as well as on cells from brains of people who died from Alzheimer's disease. The team found mice drinking water with trace levels of copper had one-third fewer LRP molecules in their brains' blood vessels, and one-third more amyloid beta in their brains than control mice after 10 weeks.

In human cells, the team discovered copper damages the protein LRP to such an extent that it stops working. Fewer LRP molecules lead to higher levels of amyloid beta, a substance that ultimately kills brain cells.

The study was presented earlier this month in San Diego during the 37th annual meeting of the Society for Neuroscience.