Many gods in "pagan" cultures had communal meals of bread and wine apart of their ceremonies. Osiris's dismembered and scattered body parts were equated with cornbread or barley while his blood was identified with beer because it was believed that the rotting pus from his body fermented Nile waters into wine. Dionysus also turned water into wine in the writings of Diodorus Siculus, Pliny The Elder, Ovid, Plutarch, and some others. Demeter was consumed as bread and Dionysus was drank as wine which Cicero actually mocked as an absurdity. In Roman Mithraism the event called the Tauroctony culminated with wheat and grapevines burgeoning from the slain bull before Mithras, Sol Invictus, and the twin torchbearers had a communal meal of bread and wine together. In Harald Strohm's book "Jesus And The Soma Sacrifice: The Indo-Iranian Roots of Early Christianity" Dr. Strohm notes parallels between the Vedic Soma Sacrifice ritual, Mithraic Tauroctony, and the Christian Eucharist. The purpose of all of these stories seems to be the consumption of blood/wine for immortality and that would explain at least in large part why blood sacrifice is a major part of Christianity.
Christianity is a disorganized mishmash of Jewish and Roman-Pagan religious traditions, which makes sense considering it was founded by a disorganized mishmash of Jews and Roman Pagans.
