 Speaking generally, the various denominations of Christians celebrate a Eucharist in which a wafer or small piece of sacramental bread from wheat bread is blessed and then eaten.A typical wafer weighs about half a gram.Wheat flour contains around 10 to 13% gluten, so a single communion wafer may have more than 50 mg of gluten, an amount that harms many people with coeliac, especially if consumed every day (see "Diet" above).