ketone body β-hydroxybutyrate has been shown in mice to increase gene expression of FOXO3a by histone deacetylase inhibition, upon which FOXO3a transcriptionally increased gene expression of the antioxidant enzymes SOD2 and catalase. Plasma levels of β-hydroxybutyrate increase with fasting or a ketogenic diet. Association with longevity Genetic variation in FOXO3 has been shown to be associated with healthspan and longevity in humans. It is found in most centenarians across a variety of ethnic groups around the world. The homologous genes daf-16 in the nematode C. elegans and dFOXO in the fruit fly are also associated with longevity in those organisms. Mice lacking FOXO3 do not show obvious accelerated aging or shortened lifespan. Association with intelligence In a meta-analysis of 78,308 individuals of European descent, a particular single nucleotide polymorphism (SNP) (rs2490272) in an intronic region of FOXO3 and neighboring SNPs in the promoter region, had the strongest associations with intelligence. Various types of tests had been used to measure intelligence. See also FOX proteins Daf-16 References Further reading ；chih长此人十二厂二 External links Forkhead transcription factors Aging-related proteins