Find Your Cruise
If you do want them to cater for gluten-free diet then you need to have this pre-arranged in advance of the sailing, apart from that can't help further.
A little bit more info: All ships have a chef dedicated to the preparation of meals for special diets. This chef will be advised by the reservations team in advance of embarkation of all passengers with special diet needs to ensure that the required ingredients are available. Once on board the headwaiter will contact these passengers to discuss and make sure these needs are met.