&gt;Maybe this &quot;Alzheimer protein&quot; is supposed to be the brain&#x27;s defenses to something much worse.<p>What could possibly be worse? What are we seeing from non-Alzheimer sufferers that&#x27;s so terrible? I don&#x27;t think there&#x27;s any evidence here that there&#x27;s some benefit to it. Its a horrible disease.<p>My dad went from occasional forgetfulness to completely falling apart in less than two years. He would get lost routinely, couldn&#x27;t remember names, had no idea what time or day it was, and developed sundown syndrome where once 6pm hit he completely went mad. He would be angry at nothing and scream at the mirror. He would rant and ramble about his past or strange conspiracy theories.  Towards the end, he lived in some weird nightmarish state almost all the time. Sundown syndrome became his norm. He died of cancer before it progressed past that point, but man, this disease is not just losing memories. It pretty much destroys your brain and acute dementia has a link with immune system dysfunction, so it eventually kills you, usually by pneumonia.<p>I doubt there&#x27;s any benefit. Evolution isn&#x27;t this wonderful process. Its a lot of crap thrown at the wall and enjoying the stuff that works and dealing with what doesn&#x27;t. There&#x27;s no mastermind or clockmaker here. There are a lot of things that go wrong with human health that has no benefit.