Why can’t my non-Catholic friend take communion when she comes to Mass with me at the university chapel?

I hear this question rather frequently from college students. I gently reply, first, in the Catholic church, we don’t “take,” we “receive,” communion. By receiving communion we are signaling, i.e., sign-ing (Sacraments are “signs”), that we are trying to live our lives according to the teachings of the Catholic faith. Communion is not the cookie at the end of the meal. Communion is much more like a fraternity or sorority pin. You can go to the GREEK party, but you don’t wear the frat’s pin unless you pledge and join the fraternity. I invite those who are not receiving communion to feel free and encouraged to come forward and receive a blessing by crossing their arms across their chest to signal to the Eucharistic Minister that they are asking for a blessing.

Here’s a video we did some time ago, on receiving communion for Catholics, which might give you some more insight into how Catholics look at the sacrament.