I'm not trying to mock religion, just people who see things in the Bible that aren't there. As if bread can't be made from other grains, or hasn't been for thousands of years. Or people who think it is the wheat rather than the sacrement that is holy.
It's certainly not Atkins friendly.
The only stipulation I know of for a Passover meal (and that is what communion symbolizes which in turn symbolizes the death of the messiah or sacrificial lamb) is that the bread must be unleavened. If you look up the word Matzah it means unleavened. Potato flour is often used in Jewish recipes.