Recently, the guy who wallpapered my office told me that the gum they use is CMC powder mixed with water. CMC powder is also used in making icecream; and since he came to know of that, he has stopped eating icecream!
50 grams of CMC diluted by more than a full bucket of water made enough gum to wallpaper the entire office!
More on CMC powder is available here - it is a man-made gum with the technical name Sodium Carboxymethyl Cellulose Gum. A companion piece on artificial strawberry flavouring - you can read here. And a little more about milk.
We eat so many chemicals that our bodies don't even decompose fast enough after burial. See this article.