Um it's definitely the saturated fat. I've got the study I can link it later. Apoe4s have different lipid metabolism.

Ya I've been hearing about that for some time.

What I think is likely more impactful is lowering saturated fat for people with the Alzheimers gene (Apoe4) -- the highest sf consumers are 1100% more likely to develop dementia than the lowest sf consumers (among Apoe4s)

Aalzheimers is largely lifestyle related. Studies have shown that exercise can help prevent MCI from developing into full on dementia. Obviously, we don't know in those cases if Alzheimers specifically was avoided, but it stands to reason.

Diet is also a huge factor. A revised diet might prevent or at least delay onset.