A study published in the Proceedings of the National Academy of Sciences is causing debate among scientists on the connections between copper intake in the diet and Alzheimer’s Disease. The study, conducted on mice, showed that a large amount of copper permitted a dementia-causing protein associated with Alzheimer’s to take hold.

The research team hails from the University of Rochester in New York, and their findings showed that mice that drank water with a high copper content had a large build-up of copper in the brain, and that the blood-brain barrier’s ability to filter out beta amyloid proteins was all but destroyed.

The lead researcher, Dr. Rashid Deane, was quoted by the BBC as saying it’s “clear that, over time, copper’s cumulative effect is to impair the systems by which amyloid beta is removed from the brain.” Even stil, extra beta amyloid protein was being produced as a result of the extra copper, and that led to “a double whammy of increased production and decreased clearance of amyloid protein.”

While Dr. Deane notes copper’s importance as an ion and would recommend not taking supplements, other scientist are less certain. A professor of bioinorganic chemistry at Keele University, Chris Exley, says that copper’s role in Alzheimer’s is by no means certain, and that “no true consensus” has been reached. His own research findings completely dispute the recent Rochester study, and he has said that “In our most recent work we found evidence of lower total brain copper with ageing and Alzheimer’s. We also found that lower brain copper correlated with higher deposition of beta amyloid in brain tissue.”

Other doctors seem disposed to agree with Exley. Dr. Eric Karran from Alzheimer’s Research UK said that “the results will need replicating in further studies [and] it is too early to know how normal exposure to copper could be influencing the development or progression of Alzheimer’s in people,” while Dr. Doug Brown concurred: “More research is needed to understand the role that copper might play in the brain.”

The L.A. Times quotes Deane himself as saying that “The key will be striking the right balance between too much and too little copper consumption,” Deane said. “Right now, we cannot say what the right level will be. But diet may one day play an important role in regulating this process.”