In particular, Ou et al. (2020) [51] found that the Akkermansia gavage, in addition to regulating the inflammation and sugar metabolism, significantly reduced the Aβ 40–42 levels in the cerebral cortex and improved the spatial and recognition memory of APP/PS1 mice, a model of Alzheimer’s disease (AD) [51]. Here, APP is linked to early-onset autosomal dominant Alzheimer disease.