I'm not disputing the findings but to me they seem oversimplified. According to the experts our brains didn't start to grow until we starting to consume meat and they grew bigger when we learned to cook it (increased bio availability). Scientist have studied our ancestors bones and determined that they lived on 80% meat and 20% vegetable matter. Probably higher than we eat today.  If protein is linked to Alzheimer's disease shouldn't we as a species have died out long before now? Seems strange that it's only really a problem in the industrial age. There is a huge number of diseases linked to the industrial age most can be linked back to chemicals that we just dump in the sea. Then through evaporation we drink it. Do you not think that the water vapor from the sea that forms clouds, would not carry some of these chemicals that later rains in our reservoirs. Or are we ignoring that because we don't want it to be true?