An allergy to shellfish, or an inability to process lactose, does not mean you must cross eating out from your list of activities on a Friday night, but it does mean you need to be a little less casual about your casual dining than people who do not have food sensitivities.

There are the obvious things to avoid, like mussels if your body reacts to shellfish, or breads and other wheat-based items if you have celiac disease.

Some experts recommend not only avoiding these things on the menu, but also skipping restaurants where they are the main option—for example, if you are allergic to nuts, skipping seafood restaurants, bakeries, or Asian or other ethnic cuisines.

Food can be wonderfully complex, and many of the things that can set off an allergic reaction or sensitivity-related illness may not be apparent in the dishes you order.

Though not specifically related to restaurant dining, the American Diabetes Association has provided a list of foods that might have gluten in them where it is not expected:

  • broth in soups and bouillon cubes
  • breadcrumbs and croutons
  • fried foods
  • imitation fish
  • lunch meats and hot dogs
  • matzo
  • most chips and candy
  • salad dressings
  • self-basting turkey
  • soy sauce
  • rice and pasta mixes

Trace amounts of the problem substance can cause illness, or even a fatal reaction, so it is a good idea to question the employees carefully about what goes in the foods prepared at their restaurant from the moment it hits the pan to when the chef puts on the finishing garnish.

You need to be careful with or even avoid sauces, dressings, marinades, and oils as toppings or cooking agents, as they rarely contain only a single ingredient. If the staff cannot be sure of what’s in it, it is better to do without than end the outing with a trip to the hospital.

It is also a good idea to be sure the staff understands that there has to be little or no exposure. Even a utensil with a trace amount of the problem substance on it could cause problems if it is used to prepare your food.                 

Lauren Wuscher, of Philadelphia, has sensitivities to gluten and soy. To help others in her situation, she created her own website——not just with food, but with cosmetics, travel, and more.

“Many times soy, gluten, and wheat hide in items such as non-stick sprays or butters that chefs use,” Wuscher said. “I was recently at a restaurant and almost ate an item that had soy in it because it was something that is normally (OK) for me to eat—green beans! But in fact, once I talked to the chef, (I) found out that the non-stick spread they use had soy lecithin in it, which I'm very sensitive to.”

Source: Avoiding Hidden Glutens When Eating Out | Healthline