As long as I'm in a mood for pseudo-science, let's cover oxides too!
Have you heard how beta-carotene binds free radicals in our bodies, thus preventing cancer and premature aging, and all sorts of other maladies? It's true!
Those free radicals are mostly oxygen. Oxygen is a lonely little molecule. It likes diverse company. When oxygen bonds with hydrogen, it does so with a bang. Giving off energy and producing water as a result. Neat huh? Oxygen will bond with pretty much anything, given any opportunity. This process is called "oxidation". Ring any bells?

Iron oxide is better known as rust. Titanium dioxide (along with iron oxide) gives sapphires their lovely blue color. Oh! and remember the whole dioxide controversy? Three guesses what the main ingredient is!

In really laymen's terms, we are rusting ourselves to death!