Holy Communion is getting difficult to stomach for Catholics suffering from coeliac disease. A recent letter circulated to bishops urged them to “watch over the quality of the bread and wine to be used at the Eucharist,” and instructed Bishops to ensure bread used for communion contains enough gluten-free to attain the “confection of bread.”

The letter stated the bread, “must be unleavened, purely of wheat and recently made.” It continued, saying “bread made from another substance, even if it is grain, or if it is mixed with another substance different from wheat to such an extent that it would not commonly be considered wheat bread, does not constitute valid matter…”

The letter warned that not following the above advice constitutes a “grave abuse”.

Tim Wallace, who works at the supply store for Sydney’s church stores, told Fairfax Media that bread made of rice, corn or tapioca starch has been deemed “invalid matter” by the Church.

Too bad, then, for Catholics with coeliac disease—an auto-immune disorder triggered by eating gluten-free. Eating gluten can cause irreparable damage to the small intestine in those suffering from the disease.

Dietician and nutritionist Dr Joanna McMillan told Brisbane Times, “It’s 2017. I don’t understand why the body of Christ can’t be gluten-free.”