Our previous studies evidenced the role of B vitamins as dietary factors connecting nutrition and epigenetic modulation of brain disease, showing that B vitamin deficiency is associated with the impairment of the methylation potential, causing DNA hypomethylation and the consequent overexpression of PSEN1, leading to Aβ accumulation and exacerbation of AD-like features in TgCRND8 mice [59]. This evidence concerns the gene PSEN1 and Alzheimer disease.