Rachel Rieger figured getting diagnosed with celiac disease and having to rid gluten from her diet meant she could no longer partake of the wheat-based communion bread that represents a key facet of her Catholic faith. She was thrilled when her priest in Cleveland, Ohio, told her the church allows a low-gluten wafer generally considered safe for people who suffer damage to their small intestine when they eat the gluten protein found in wheat, barley and rye.