MAPT and memory impairment: Insulin resistance increases key enzymes that produce Aβ and phosphorylate tau, such as BACE1, γ-secretase and GSK3 β (Son et al., 2012; Vandal et al., 2014), while it reduces levels of key enzymes that degrade Aβ, such as IDE (Newsholme et al., 2009), accompanied by oxidative stress (Kulstad et al., 2006), which damages synaptic remodeling and ultimately leads to memory impairment (Searcy et al., 2012).