New research suggests that too much copper in our diets is harmful when it comes to Alzheimer's, reports the BBC. That's especially worrying because copper is so tough to avoid: It's found in fruits, vegetables, red meats, shellfish, vitamin supplements—and of course, water, thanks to copper pipes. Researchers found that mice with more copper in their water had more copper collecting in their brains, weakening the barrier that keeps out harmful toxins. Plaques of the protein beta amyloid are common in Alzheimer's patients' brains, and increased copper intake made it more difficult for the brain to get rid of the stuff.
"It's a double whammy of increased production and decreased clearance of amyloid protein," says researcher Rashid Deane, calling his findings "pretty scary." The good news: Drugs currently being tested can help flush copper from the system, perhaps offering a weapon against Alzheimer's, he tells the Los Angeles Times. But other experts question the new study, saying more research is needed. "Considering copper is a vital mineral for the body, people should treat these results with caution and not cut it out of their diet," says one.