It seems like having a gluten intolerance is something that we’re barely hearing about, but now even the Catholic church is talking about it. Pope Francis issued a letter in mid-June saying that all bread used during communion must have at least some gluten, which is a naturally occurring protein in wheat, that is commonly used in products such as bread, pasta, and cereal. About 2.7 million Americans avoid gluten, and about half of those have celiac disease, which is why some Catholics have requested a gluten-free wafer during communion.
“Hosts that are completely gluten-free are an invalid matter for the celebration of the Eucharist,” wrote Cardinal Robert Sarah on behalf of the pope. Low-gluten hosts, he added, can be used, “provided they contain a sufficient amount of gluten to obtain the confection of bread without the addition of foreign materials and without the use of procedures that would alter the nature of bread.”
According to the Catholic church rules, the recipe for the bread used during communion should be made purely of wheat–no substitutions. Surprisingly, people can buy gluten-free communion wafers online, but this really defeats that purpose of having to go to church to receive the holy communion. The letter states that the bread and wafers “must be unleavened, purely of wheat, and recently made so that there is no danger of decomposition.” People that “are completely gluten-free are an invalid matter for the celebration of the Eucharist.” Yet, low-gluten wafers and bread may be used. 
“Christ did not institute the Eucharist as rice and sake, or sweet potatoes and stout,” said Chad Pecknold, a theology professor at Catholic University. Some theologians argue that the bread and wine are symbolic and that it’s not a big deal if they don’t eat the bread. “It may seem a small thing to people,” Pecknold says to the Washington Post. “But the Catholic Church has spent 2,000 years working out how to be faithful to Christ even in the smallest things. To be vitally and vigorously faithful … is something which is simply integral to what it means to be Catholic.”