On Mondays, I answer questions frequently asked by those considering a return to the Catholic Church. How do I know this stuff? I was away for more than 30 years myself, and am the co-author of When They Come Home: Ways to Welcome Returning Catholics, a book for pastors and parish leaders interested in this ministry.
Why are non-Catholics excluded from taking communion at our Church? Should I take communion if I’m attending a wedding or other service at a Protestant church?
As Catholics, we believe in Christ’s true presence in the Eucharist. Our Protestant 
brothers and sisters believe the Eucharist is a symbol, or that it serves as both Christ’s presence and a symbol. Until the day our churches are united, non-Catholics should receive our sacrament only in extremely rare situations in consultation with a priest. It’s simply a matter of respect; when we say “amen” after receiving the host or wine, we are saying we believe it truly is the body or blood of the Lord.
And when we are at a non-Catholic Christian church, we are mindful that their views of Christ’s presence in the Eucharist are different from ours. We should respect their beliefs, but not profess to adopt or accept them by taking communion at their services.
