A connection of BC metabolism with metabolic health through the regulation of specific miRNAs in the liver is suggested by the fact that the ablation of key enzymes in carotenoid metabolism (BCO1 and BCO2) induces hepatic steatosis in mice by altering the farnesoid X receptor/miR-34a/sirtuin 1 axis [13]. The gene discussed is BCO1; the disease is fatty liver disease.