I believe that rules are an intrinsic part of any religion.  The word religion, itself is Latin for religio...to rope together.  Imagine if there were no rules within the family..chaos maybe, not to mention society as a whole.  The child sexual abuse by clergy now has "rules" enforced (in our country, at least) and rightly so..but other rules like diets perhaps should follow the saying of St. Benedictine.."all things in moderation".  So if someone is allergic in any manner to the host and is a known anaphylactic to its ingredients than I'm sure the rules could be bent.  

I don't know, but maybe too much is placed on anything but Jesus..maybe we're becoming too exact in the wrong areas...when I use to work with the poor and was invited for a meal, there were a few times I would have preferred not to have eaten some things..but I ate..I always thought it a great honour, to be invited...it was kinda Christ filled.