Researchers at the University of Bath have discovered new information about a poorly understood but common cause of dementia.

In a project funded by the Alzheimer's Research Trust, the Bath scientists have been studying the damaging effects of a protein, called alpha-synuclein, that builds up in the brains of people with Lewy Body disease and Parkinson's disease.

Their findings, published in this month's FASEB Journal, could have implications for the 25,000 people in the UK with Lewy Body disease, which causes distressing hallucinations, confusion and movement problems.

Until now, there has been little understanding of how the protein harms the brain.

The team has shown for the first time that an interaction between the protein and naturally-occurring trace metals creates a "toxic bomb" which damages brain cells.

The findings will help scientists understand what happens in the brain in both Lewy Body and Parkinson's disease and could lead to new ways to develop treatments. One particular approach could be to try to somehow block metals in the brain from joining with the protein.

Professor David Brown, who led the team at the university, said: "The results show the critical importance of metal ions and their interaction with alpha-synuclein in causing death of brain cells. They also show that small aggregates of proteins are more important than the larger ones that scientists have previously thought crucial."

Trust chief executive Rebecca Wood said: "Lewy Body disease and Parkinson's are very distressing conditions and this Bath research is a vital step in the journey towards defeating them. By improving our understanding of the processes that take place in the brain during these diseases, we arm ourselves with the knowledge we need to push on for new treatments. Research into dementia is severely underfunded, yet the small amount under way is making excellent progress."