Catholics on a gluten-free diet may want to skip the line when receiving Holy Communion during Mass celebration. The Vatican has decreed that the small wafers, or hosts, used in the ceremony must contain gluten, reports the BBC. The directive went out to bishops worldwide in a letter posted by Vatican Radio. "Hosts that are completely gluten-free are invalid matter for the celebration of the Eucharist," reads the letter, which spells out that the bread "must be unleavened, purely of wheat, and recently made so that there is no danger of decomposition." Using anything else to make it gluten-free is thus off-limits. Low-gluten wafers are fine, however. (More Vatican stories.)