Talk to your caterers
If you know a larger portion of your guests will have dietary restrictions, then it's best to speak to your caterer early so they can accommodate their needs from the get-go. Most caterers should have no problem tailoring their menus to suit specific needs, and they will be able to provide helpful suggestions and options so that you won't ever feel like you're settling for something you wouldn't have wanted anyways!

Keep food separate and label
If you're having a buffet, make sure the food at your reception is separated and labeled appropriately to avoid cross-contamination. If you're having a plated dinner, make your guest understands whether or not their meal contains any issue for them. You'll need to coordinate place settings with the caterer.