PSEN1 and Alzheimer disease: Multiple effects of DHA have been shown to antagonize AD pathogenesis, including increasing cerebral blood flow, decreasing Aβ deposition and tau phosphorylation by inhibiting presenilin 1 (PS1) and c-Jun N-terminal kinases (c-JNK), reducing activities of β-and γ-secretase while enhancing APP cleavage by α-secretase, increasing dendritic spine densities and restoring synaptic function in the hippocampus [45,46,47].