The loss of oleic acid has been reported to favor BACE1 activity and increase the Aβ 1-42/Aβ 1-40 ratio, whereas dietary oleic acid supplements increased the Aβ 1-40/Aβ 1-42 ratio and reduced the levels of BACE and presenilin, as well as the number of amyloid plaques in AD brains (Amtul et al., 2011). This evidence concerns the gene BACE1 and Alzheimer disease.