Understanding Gluten a Little

There's a Sandra Boynton book, called "Hey, Wake Up!" which seems to be the book of the moment right now. I believe it's supposed to be read in the morning, but we read it before bed. Anyway, there's a page where four different animals are eating different things for breakfast. One of the animals only eats cereal. Gabby pointed out that the other animal can't eat it and when I asked why she said it has gluten in it. As always, I made the connection that for some people gluten makes their tummy feel icky and she agreed. I thought that was interesting... she's getting it in her own little 2 1/2 year old way...