Additionally, dietary supplementation with XN has been shown to improve spatial, as well as reversal, learning in a Morris water maze, in young wild-type mice (Miranda et al., 2018; Zamzow et al., 2014), and to reduce cognitive injury associated with alterations in the gut microbiome in a mouse model of Alzheimer's disease transgenically expressing human amyloid precursor protein and presinilin 1 (Liu et al., 2022). This evidence concerns the gene APP and early-onset autosomal dominant Alzheimer disease.