From Nature:
It freshens breath, protects teeth and even, if you believe the commercials, makes you immensely popular. But Finnish researchers are hoping that chewing gum could soon pull off an even more ambitious trick: helping to stave off cancer. They have made a gum containing a compound that mops up a chemical called acetaldehyde, which has been linked to cancers of the mouth, oesophagus and stomach. The active ingredient, called cysteine, is slowly released through chewing the gum.
The anti-cancer chew could help those most at risk, such as smokers and heavy drinkers, suggests Mikko Salaspuro of the University of Helsinki, who developed the idea with his colleague Martti Marvola. Smoking and drinking are linked to up to 80% of these cancers in developed countries. Smoke and alcohol both raise the levels of acetaldehyde in the mouth and upper digestive tract. Cysteine, a building block of proteins, reacts with the compound to take it out of harm’s way.
More here.