What is the significance of Jesus 's action in sharing bread and wine ?
Transubstantiation ( in Latin , " transsubstantiatio " , in Greek μετουσίωσις metousiosis ) is the change whereby , according to Catholic doctrine , the bread and the wine used in the sacrament of the Eucharist become , not merely as by a sign or a figure , but also in reality the body and blood of Christ .