So you can’t eat bread. Or donuts. Or English muffins. You have celiac disease, or a lesser malady titled simply “gluten sensitivity.” Or worse, you could be suffering from terminal cancer and nearing the end stage of life, and can no longer digest solid foods. How can you receive the consecrated host, the Holy Eucharist?

Or maybe this is the problem: You are a [recovering] alcoholic. You get along just fine, thank you, after years of struggle to overcome addiction; but the one stipulation – the one thing that keeps you sober – is that you never drink even a drop of alcohol. Just a single taste of alcohol could trigger a plunge into drunkenness from which there's no easy way out. How can you receive the consecrated wine, the Blood of Christ, during the Mass?

Dietary restrictions like these are not uncommon. A 2012 study by doctors at the Mayo Clinic found that roughly 1.8 million Americans suffer from celiac disease. An estimated 6.2 percent of adults over 18 – about 15.1 million people – have an alcohol use disorder.

Celiac disease typically results in indigestion, gas, diarrhea or constipation, and discomfort; but at its most serious, exposure to the protein in wheat, rye or barley can trigger an immune response that can permanently damage the small intestine. The result, for the gluten-intolerant Catholic with celiac disease, is sometimes a matter of bloating and abdominal discomfort.

But does fear of falling ill mean that a faithful Catholic must abstain from that most valuable spiritual food, the Holy Eucharist?

The Church’s Pastoral Response

While most are able to receive Christ in the Eucharist in both forms – both the consecrated host and the wine – those with certain disorders may legitimately fear that ingesting the host will result in deleterious side effects. The Catholic Church acknowledges the health risks for some, and offers solutions.

In a July 24, 2003 letter to presidents of the episcopal conferences, then-Cardinal Joseph Ratzinger, speaking as Prefect of the Congregation for the Doctrine of the Faith, explained the acceptable use of gluten-free hosts and mustum:

1. Hosts that are completely gluten-free are invalid matter for the celebration of the Eucharist.

2. Low-gluten hosts (partially gluten-free) are valid matter, 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.

3. Mustum, which is grape juice that is either fresh or preserved by methods that suspend its fermentation without altering its nature (for example, freezing), is valid matter for the celebration of the Eucharist.

If You Just Can't Eat Bread

If a highly gluten-sensitive layperson is unable to receive Communion under the species of bread, even low-gluten hosts, that person may – according to the future Pope Benedict – receive Communion under the species of wine only. It is also possible to receive only a small piece broken off of the host, thus reducing one's intake of the allergen found in gluten. Since Jesus is fully present, Body, Blood, Soul, and Divinity, in both species (in the bread and in the wine), the celiac sufferer who receives only a small sliver of the consecrated host or only the Precious Blood does not receive Jesus into himself only in part, as contrasted with another communicant who consumes both the bread and the wine.

The situation for a priest who is strongly gluten intolerant is more difficult. According to the Common Norms outlined in Cardinal Ratzinger's 2003 letter,

A priest unable to receive Communion under the species of bread, including low-gluten hosts, may not celebrate the Eucharist individually, nor may he preside at a concelebration. Given the centrality of the celebration of the Eucharist in the life of a priest, one must proceed with great caution before admitting to Holy Orders those candidates unable to digest gluten or alcohol without serious harm.

It would appear, then, that an ordained priest – who has the obligation to celebrate Mass daily – must, if he suffers from an extreme wheat allergy, refrain from exercising that central role of his priesthood.

Drink Mustum, If You Must

Mustum is virtually indistinguishable from regular altar wine, but fermentation has been suspended early in the process, with the result that its alcoholic content is less than that found in most table wines – usually less than 1%.

With permission from his bishop, a priest or deacon may choose to use mustum in celebrating the Mass; although Cardinal Ratzinger explained that if a Mass is concelebrated, or if others are to receive the Precious Blood, then the priest should consecrate the contents of two chalices – one with mustum, the other containing traditional altar wine. An exception made for is treatment centers for clergy and religious, such as Michigan's Guest House, where all residents are facing the challenge of addiction recovery. In such centers, a blanket provision may be approved, permitting all participants at Masses on campus to receive the Precious Blood in the form of mustum.

Resources for Low-Gluten Hosts and Mustum

The U.S. Bishops, on their website, explain what resources are available for those with wheat or alcohol intolerance. The site currently lists four approved sources for low-gluten hosts, including the Benedictine Sisters of Perpetual Adoration in Missouri. Two sources – Mont La Salle Altar Wines in California, and Monks Wine and Candles in Illinois – sell mustum for use at Mass.

The USCCB cites Canon 912, which states, “Any baptized person not prohibited by law can and must be admitted to Holy Communion.” It is important for pastors to make every effort to accommodate and normalize the experience of Communion for the faithful, including those suffering from celiac disease. Such can certainly be done within the norms of Church teaching.