“Just as bread that comes from the earth, after God’s blessing has been invoked upon it, is no longer ordinary bread, but Eucharist, formed of two things, one earthly and the other heavenly: so too our bodies, which partake of the Eucharist, are no longer corruptible, but possess the hope of resurrection.” …AGAINST HAERESIES 4, 18, 4-5
Here’s a few other citations to factor in.
He took that created thing, bread, and gave thanks, and said, “This is My body.” (Mt 26:26ff) And the cup likewise, which is part of that creation to which we belong, He confessed to be His blood, and taught the new oblation of the new covenant; which the Church receiving from the apostles, offers to God throughout all the world, to Him who gives us as the means of subsistence the first-fruits of His own gifts in the New Testament,
[St. Irenaeus of Lyons, *Adversus Haereses, IV, 17, 5]
Moreover, how could the Lord, with any justice, if He belonged to another father, have acknowledged the bread to be His body, while He took it from that creation to which we belong, and affirmed the mixed cup [wine and water] to be His blood? And why did He acknowledge Himself to be the Son of man, if He had not gone through that birth which belongs to a human being?
[St. Irenaeus of Lyons, *Adversus Haereses, IV, 33, 2]
“He has declared the cup, a part of creation, to be his own blood, from which he causes our blood to flow; and the bread, a part of creation, he has established as his own body, from which he gives increase unto our bodies. When, therefore, the mixed cup [wine and water] and the baked bread receives the Word of God and becomes the Eucharist, the body of Christ, and from these the substance of our flesh is increased and supported, how can they say that the flesh is not capable of receiving the gift of God, which is eternal life–flesh which is nourished by the body and blood of the Lord, and is in fact a member of him?”
[St. Irenaeus of Lyons, *Adversus Haereses, V, 2, 2-3]