In earlier work, we demonstrated that asymptomatic APOE4 carriers experience more pronounced gut dysbiosis than non-carriers, including those with APOE e3 alleles (APOE3), and prebiotic diet may mitigate the risk for AD by reducing the gut dysbiosis in the APOE4 mice (Hoffman et al., 2019; Yanckello et al., 2021). This evidence concerns the gene APOE and Alzheimer disease.