Very interesting, I had not read such things about gum before.
It makes me wonder, how this could relate to teeth grinding? When I was a child, my mom told me that I would sometimes grind my teeth during sleep (she could hear it). I have also met people who had teeth grinding issues (and also many stimulant drug abusers have this issue). Perhaps there is something more to this automatic reaction in some people? Like the body is having a hard time breaking something down, and needs to secrete more enzymes or some such...perhaps also this could lead people to chew gum, when additional support is needed (I'm thinking about the SAD diet that so many are on these days).
Obviously, the toxic chemicals are super bad, but perhaps there is another reason 'chewing gum' has been so popular throughout the ages, and perhaps it is not entirely bad?