I'm not Bulgarian, but French, and I have spent most of my life in Europe, and never met somebody there worrying about walnuts in a cake (or any other nut). Some people with strong lactose intolerance (worldwide, most people are lactose intolerant), a friend of mine is allergic to coca-cola (really), maybe a girl with a cucumber allergy (but pretending she hates the taste), and I think that's all.

So I would say for continental Europe, food allergies are not common.

There is another difference between Europe and the US regarding peanuts : most people never buy peanut butter in Europe. And we avoid giving peanuts to children before the age of 4 or 5. The younger you start eating peanuts, the more chance you have to become allergic to them, so please don't feed your child with peanut butter.

Ruth : regarding your experience in Germany, you're speaking only about elderly people ? For my grand-parents, food dislike is not an acceptable attitude in children... except for Jerusalem Artichoke or Rutabaga. These 2 vegetables been notorious as "war time food" ; nowadays they are very hard to find (and expensive, too), because of this reputation. Most french people born after WWII never ate them, and the one who tried say that in fact, they are not that bad. But for grownup, there is no problem about a food dislike in France (or Belgium).