The Vatican has confirmed a 2003 directive, instructing parishes that they can’t serve truly gluten-free breads but are allowed to offer believers low-gluten substitutes during communion. The Church saw the need to clarify this policy given that, “[T]he confusion can be great when these ‘breads’ are advertised as gluten-free alongside what are described as gluten-free but are in fact low-gluten altar breads,” according to the Catholic Church in England and Wales.
“In both the United States and the European Union, the description “gluten-free” can be legally applied to foods made with wheat starch from which almost, but not absolutely, all gluten has been removed — the upper limit is 20 parts per million,” says The New York Times. “The Catholic church will allow bread of this kind to be used for communion.” However, completely gluten-free options made from rice, tapioca or potato flours are not permitted.
If parishioners have Celiac Disease and can’t tolerate any amount of gluten, they’re permitted to only drink the wine at mass. Catholics make up the largest U.S. Christian denomination at roughly 68 million people.