The apostles did not teach that the bread and wine of communion changed substance and became the actual body and blood of Jesus. That idea developed much later.
If you go to a Catholic apologetic's web site you will find quotes from some of the early church fathers that seem to indicate that they taught the real presence of Christ in the elements. The problem with those quotes is that they are taken out of context. Teaching based either on sacred scripture of the early church fathers taken out of context will lead to incorrect doctrine.
The idea of the real presence of Christ in communion is important to Catholic theology because that then requires an apostolic priesthood to administer the sacrament. This leads us to think of the Church not as a living organism comprised of all who have confessed Jesus as Lord and Savior but rather as an institution headed by popes and bishops who direct and administer the distribution of graces to the flock.
Check here for an excellent and easy to understand article about the writings of many of the early church fathers in their context about the Lord's supper. I had always wondered about this and was glad to come across it.
