https://scitechdaily.com/scientists-discover-way-to-reverse-chemical-process-linked-with-alzheimers-disease/

"By watching Alzheimer's-related protein clumping unfold second by second, researchers have uncovered new clues about the role of metal ions."

This is pretty wild research. For many years, there have been suspicions about aluminum, but apparently the most worrisome metal is copper. Lots of research left to do, but lately there seems to be actual progress on AD.

>copper

Lots & lots of copper piping in water systems prior to poly, pex, cpvc (mid-1980s).  Most of it soldered with high lead content solder.  Or so our county found out when they started researching lead in residential water.

>> suspicions about aluminum

For that reason my mother refused to wear commercial deodorant. /TMI

>copper

That took me by surprise, I've been worried about plastic piping.  Dang, indoor plumbing can mess you up.