Q: Do then the bread and wine become the body and blood of Christ?
A. Not at all; but as the water of Baptism is not changed into the blood of Christ, neither is the washing awa of sin itself, being only the sign and confirmation thereof appointed by God: so the bread of the Lord's Supper is not changed into the very body of Christ, though, agreeably in tha nature and properties of the Sacraments, it is called the body of Christ Jesus.<.i>
Some have summarized this--quite accurately--as the doctrine of the Real Absence.
However, could you please be more specific as to which Christian denominations you believe do not partake of the Holy Eucharist as it is written in the Holy Bible?