Environmental Matters in the Commonwealth of Kentucky

On May 17, 2008, Canada will publish a list of 17 substances that may be labeled as toxic in a draft report on risk assessment.   Vinyl acetate — commonly used as a base in some chewing gums — could be on that list.  The substance itself is not a direct ingredient in chewing gum. But vinyl acetate is used to make the polymer that’s used as a base in gum.  Polyvinyl acetate is a rubbery synthetic polymer prepared by polymerization of vinyl acetate.  Canada is apparently looking at research from the International Agency for Research on Cancer (IARC), the World Health Organization’s cancer research arm, which has found some evidence that vinyl acetate may have caused tumors in rats.  There has been no link demonstrated between vinyl acetate and cancer in humans.  No comment yet from the U.S. Food and Drug Administration on Canada’s potential list of 17 additional toxic substances.

 According to the U.S. Food and Drug Administration’s website, people are often chewing on synthetic polymers—styrene-butadiene rubber, polyethylene, polyvinyl acetate—with a bit of natural latex thrown in.   The specific ingredients in gum are not listed on the back of the package.   Federal regulations allow a typical list of ingredients on a pack of chewing gum to read like this: gum base, sugar, corn syrup, natural and/or artificial flavor, softeners, and BHT (added to preserve freshness).  This lack of clarity in listing specific ingredients in chewing gum is largely due to manufacturers’ desire to protect their trade secret formula.

 We took a look at 21 CFR 172.615 to find the various ingredients that may compose chewing gum base.  The following synthetic chemicals that may comprise chewing gum base.   Masticatory Substances Synthetic (makes the gum chewy):  butadiene-styrene rubber, isobutylene-isoprene copolymer (butyl rubber), paraffin, petroleum wax, petroleum wax synthetic, polyethylene, polyisobutylene, polyvinyl acetate

Plasticizing Materials (gum softeners): glycerol ester of partially 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 rosin, pentaerythritol ester of gum or wood rosin, rice bran wax, stearic acid, Sodium and potassium stearates, synthetic terpene resin, butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, sodium sulfate, and sodium sulfide. 

The FDA regulation goes on to say that in addition to the substances listed above, chewing gum base may also include substances generally recognized as safe in food.  The label and labeling of the food additive shall bear the name of the additive, “chewing gum base.” As used in this paragraph, the term “chewing gum base” means the manufactured or partially manufactured nonnutritive masticatory substance comprised of one or more of the ingredients named and so defined above.