This is the list of 'permitted ingredients' in gums and chewing gums.
Arabinogalactan
Chewing gum base

* natural masticatory substances of vegetable origin chicle, chiquibul, crown gum, gutta hang kang, massaranduba balata, massaranduba chocolate, nispero, rosidinha, Venezuelan chicle, jelutong, leche caspi (sorva), pendare, perillo, leche de vaca, Niger gutta, tuno, chilte, natural rubber (smoked sheet and latex solids) synthetic masticatory substances butadiene-styrene rubber, isobutylene-isoprene copolymer (butyl rubber), paraffin, (synthetic) petroleum wax, polyethylene, polyvinyl acetate

* plasticizing materials (softeners) glycerol ester of dimerized rosin, glycerol ester of partially hydrogenated gum or wood rosin, glycerol ester of polymerized rosin, glycerol ester of gum rosin, glycerol ester of tall oil rosin, glycerol ester of wood rosin, lanolin, methyl ester of rosin, partially hydrogenated, pentaerythritol ester of partially hydrogenated gum or wood resin, pentaerythritol ester of gum or wood rosin, rice bran wax, stearic acid, sodium and potassium stearates, synthetic and natural terpene resins

Carrageenan
Carrageenan with polysorbate 80
Salts of carrageenan
Furcelleran
Salts of furcelleran
Gellan gum
Xanthan gum

Here is a real chewing gum recipe:
For soft chewing gum [without the flavour coating]:
    Ingredients:
    Gum base 30% 
    Erythritol 55%
    Maltitoisyrup13%
    Glycerine 2%

Now you can look it up and find out some of what you really ARE eating.  I haven't been able to trace all of the gum ingredients in English yet.

Swallowing chewing gum
Children and chewing gum do not go together.  Under 5 years of age they cannot cope with putting food in their mouth and not swallowing it.  They swallow by instinct.  It only takes a few bits of gum for problems to start. Sometimes a child will swallow a piece of gum just to get a new piece.  Keep count, or make a limit of one piece only - and not every day.  Why is there no warning on packets 'DO NOT SWALLOW GUM' ?

If a young child has constipation and has had pieces of chewing gum, consider the possibility that they may have swallowed the chewing gum.  A child should not be given gum until they are old enough to understand the importance of not swallowing it.  It doesn't dissolve and it is extremely difficult to digest.

Dr. David Milov, author of a study on children and chewing gum said: "The child may be thought to have a slow colon but go unrecognised as having 'the works' gummed up.  There had been several cases of young children with bowel blockages that had brought to his attention that a study needed to be made of the problem.

In one extreme case, doctors surgically removed coins trapped in lumps of gum from a toddler's oesophagus, the tube that carries food to the stomach.  Swallowing gum can also cause chronic constipation, abdominal pain, gas, and mouth ulcers.

In adults, the problem is not so great because adults can digest more complex foods and have wider or larger intestines.  Still, adults should not swallow chewing gum either.

The ingredients of some gums can be harmful to young children.  Even if these flavours are not available here, you may come across them overseas or have them brought as a gift by an overseas visitor.

1. Liquorice flavouring can cause high blood pressure.
2. Cinnamon flavouring can lead to mouth sores.
3. Sorbitol, the sugar-free sweetener, has been linked to diarrhoea.

Dental problems caused by excessive chewing include injury to teeth, fillings, and braces.  It is not a good habit for a child to be always chewing as it may encourage them to be eating constantly.