Pre-clinical data support that retinoids might contribute to development and progression of AD: for example, vitamin A deficiency evoked in adult rodents cognitive impairment (Jiang et al., 2012; Hou et al., 2015) and a shift towards the amyloidogenic processing of the amyloid precursor protein (APP; Reinhardt et al., 2016). This evidence concerns the gene APP and vitamin A deficiency.