In autopsies to Alzheimer patient brains we can see the small arteries of the brain clogged with fat and colestrol, here is a video showing this with pictures - https://youtu.be/WhtpyVhlu28?list=PL5TLzNi5fYd8E6GHQcmIWYGE7...
If plaque building in main arteries can cause heart atacks, the exact same blood is getting to the brain - imagine what it will do there.
If anyone here has Alzheimer in the family and would like to preventively change their diet, have a look at this other video from that playlist - https://www.youtube.com/watch?v=t-noCw4LsY4&list=PL5TLzNi5fY...
In summary, there are strong indications that a whole food plant based diet low in fat is the best-known way to prevent Alzheimer's and even alleviate the symptoms.
Hope for Alzheimer Patients: https://nutritionfacts.org/2017/12/26/hope-for-alzheimers-pa...
It's important that the diet is not only plant based, but low in fat as for example there is a lot of Alzheimer's in India where a large part of the population is vegetarian.
This has been linked to ghee (clarified butter), as per this video:
Oxidized Cholesterol as a Cause of Alzheimers Disease - https://www.youtube.com/watch?v=Y15yI5LLlNY