The Catechism of the Catholic Church
III. The Eucharist in the Economy of Salvation
The signs of bread and win
1333 At the heart of the Eucharistic celebration are the bread and wine that, by the words of Christ and the invocation of the Holy Spirit, become Christ’s Body and Blood. Faithful to the Lord’s command the Church continues to do, in his memory and until his glorious return, what he did on the eve of his Passion: “He took bread….” “He took the cup filled with wine….” the signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ; they continue also to signify the goodness of creation. Thus in the Offertory we give thanks to the Creator for bread and wine, fruit of the “work of human hands,” but above all as “fruit of the earth” and “of the vine” – gifts of the Creator. the Church sees in the gesture of the king-priest Melchizedek, who “brought out bread and wine,” a prefiguring of her own offering.
But do they really believe it? It has been my long standing position that Christians don’t really believe what they throw out there, no matter how much they claim they do. This is one of the crazier things the Catholics claim….and they even claim to have evidence for it. Example: http://en.wikipedia.org/wiki/Miracle_of_Lanciano
So why don’t I think they believe their own little miracle? Well that’s simple, they have been working for decades to find a gluten free way to make the host. If it changes to Jesus’s body there would be no need for this.
They finally have a recipe that works too: Benedictine nuns discover way to produce low-gluten Communion hosts | Gluten Free Works
Like I said, I don’t think they really believe what they sell. Either it changes to Christ and thus has no wheat in it, or it stays the cracker it started out. I have a problem with claiming it is both. And this is great evidence that they don’t.