In a study published in the September 13, 2011 issue of the journal Neurology, researchers report that people with high levels of cholesterol, found only in animal-based dietary fats, are at a higher risk of developing Alzheimer’s disease.

http://medicalxpress.com/news/2011-09-reveals-link-high-cholesterol-alzheimer.html
http://www.webmd.com/cholesterol-management/news/20110912/cholesterol-levels-linked-brain-changes-alzheimers-disease