Here's my 2 sats - Alzheimers (the most common of the dementias) is actually a relatively new disease. It was named after Alois Alzheimer, who described the first case he found.

And when was that first case? In 1906! In other words, a NEW DISEASE.

Based on a lot of what I've read, it's a result of increasing consumption of sugar. Nowadays, they're starting to call it Diabetes, type 3.

Take a look at my recent post: Alzheimers is a NEW disease - here's how to avoid it

Avoid sugar like the plague. With that, you'll probably avoid Alzheimers as well.