We have also observed better cognitive function with higher habitual plant-sourced nitrate intake, in an APOE contingent manner, in 1254 individuals followed for 126 months in the Australian Imaging, Biomarkers, and Lifestyle (AIBL) Study of Ageing, a cohort study focusing on factors that determine the development of Alzheimer's disease [8]. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.