I will throw and interesting wrinkle into this discussion.
I am allergic to the sulfites in wine. ALL cruise lines receive their wines (including French and Italian) via agents in the United States. All U.S. wines sold must contain sulfites (a preservative). Therefore, ALL wine served, on any ship catering to US customers, contains sulfites.
I notified HAL of my allergy after cruising with them in Europe. They had offered a 'dinner package' of wine (which included French wine). Since I was cruising in Europe, I thought that the French wine would come directly from France (not via the US) and NOT contain sulfites. Was I wrong.
Since we were cruising Europe, I asked the Matr' de, if it would be possible for me to pick up some European wine (no sulfites) while we were in port and have it served to us during subsequent dinners on the cruise. I explained my allergy and showed the letter that I had sent about the allery to the cruise line prior to the cruise. My wishes were granted. MY WINE was served to me during dinner. Of course, the wine steward and matr' de got HUGE tips from us which offset their loss of revenue on the sale of the wine by the ship (and our financial 'savings' by buying the wine locally).
The cruise ships will work with you for health problems. Just a note: It is very important to tell the cruise line about allergies to sulfites. Many salads use sulfites to 'stay fresh'. You need to know where sulfites may be used in the kitchen during preparation, wine is not the only place where you can find sulfites on the ship's food. If you are prepared, you can order 'around' your allergies.