PSEN1 and Alzheimer disease: As observed for the changes in the brain lipidome, the dietary effect on amyloid Aβ1–40 levels in APP/PS1 animals was also dependent on circulating estradiol, indicating that there is an interaction between the protective effect of estradiol and the intake of a DHA-enriched diet with a low n-6/n-3 PUFA ratio in an AD animal model.