Effects on health

Dental health

Sugar-free gum sweetened with xylitol has been shown to reduce cavities and plaque.^[10] The sweetener sorbitol has the same benefit, but is only about one third as effective as xylitol.^[10]
Food and sucrose have a demineralizing effect upon enamel that has been reduced by adding calcium lactate to food.^[11] Calcium lactate added to toothpaste has reduced calculus formation.^[12] One study has shown that calcium lactate enhances enamel remineralization when added to xylitol-containing gum,^[13] but another study showed no additional remineralization benefit from calcium lactate or other calcium compounds in chewing gum.^[14]
Other studies^[15] indicated that the caries preventive effect of chewing sugar-free gum is related to the chewing process itself rather than being an effect of gum sweeteners or additives, such as polyols and carbamide.
Over 80% of cavities occur inside pits and fissures in chewing surfaces where food is trapped under chewing pressure and carbohydrate like sugar is changed to acid by resident plaque bacteria but brushing cannot reach.^{[citation needed]}

[edit] Possible carcinogens

Concern has arisen about the possible carcinogenicity of the vinyl acetate (acetic acid ethenyl ester) used by some manufacturers in their gum bases. The Canadian government has classified the ingredient as a "potentially high hazard substance."^[16] Currently the ingredient can be hidden in the catch-all term "gum base".

[edit] Swallowed gum

One old wives' tale says that swallowed gum will remain in a human's stomach for up to seven years, as it is not digestible. According to several medical opinions, there seems to be little truth behind the tale. In most cases, swallowed gum will pass through the system as fast as any other food, but can be a little slower.^[17] There have been a few cases where swallowing gum has required medical attention, but these cases are more or less related to chronic gum swallowers. One young boy swallowed several pieces each day and had to be hospitalized,^[18] and another little girl required medical attention when she swallowed her gum and four coins, which got stuck together in her esophagus.^[17] As long as the mass of gum is small enough to pass out of the stomach, it will likely pass out of the body easily