While I agree that some people are gluten sensitive, most of these people who don't have Celiac are really just sensitive to wheat. Not all of them, but many of them. The problem now is, because gluten free has become a fad, it's become harder to tell who has a real problem and who has been told they have a problem they don't have. Fads can be toxic, too. The additives problem is also an interesting one -- for Celiac sufferers this can be really debilitating, but if you're problem is a lesser one there's so little gluten in these additives it's an interesting question whether it's really enough to trigger any reaction. I don't know the answer, and I don't think anyone else does either because the problem of wheat is never accurately addressed. As I've said before, I used to have a lot of customers who had been told they were gluten sensitive but who were eating gluten containing foods without any problem without even knowing it -- they're problem was just wheat. Spelt, for example, was okay for many of them, and it has more gluten than wheat. So it remains an interesting question but one that can't be answered very well in the current fad-driven internet driven environment.
To be gluten sensitive doesn't mean you have to have celiac disease.
Some cheese, yogurt, whipped cream and processed dairy products may contain gluten from food additives.
Ingredients that may contain gluten have names like malt, caramel color, dextrin, fat replacer, food starch, flavoring or stabilizers.
http://www.glutenfreeliving.com/nutrition/recipes/
There are a ton of books out there for this, as it's quite a fad these days even for people who don't have Celiac, so I'd look into that. But cooking gluten free isn't any different from cooking with gluten unless you're making bread or cookies -- most foods don't contain gluten so you're already eating mostly gluten free unless all you eat is bread and pasta. And pasta is readily available made out of gluten-free grains, unlike bread, which is quite different gluten-free. In other words, using brown rice is still using brown rice. Spices still taste the same. You're just switching grains, not everything.