

Yes, this is certainly one of the traditional ideas about the Mithraic
cult (although not the only one.)  It had many elements that seem
to have been borrowed by Catholicism (e.g. the Mass, communion, the
sharing of a sacred meal, consecration of bread and wine, etc.)

For quite an amusing novel that uses this same idea, check out:

The Covenant of the Flame
by David Morrell.

It has some quite interesting occult bits, and lots of killing.
I won't spoil it by revealing the ending, but I will say that it
is relevant to Mithraism.