Dr. K: Sugarless gum tends to help fight cavities

DEAR DOCTOR K: I always thought chewing gum was bad for my teeth. But then a friend told me it actually helps prevent cavities. Who’s right?

DEAR READER: My mother would have said your friend is wrong. But actually your friend is partly right. The answer depends on the type of gum you’re chewing.

Bacteria normally reside in dental plaque, the sticky deposit that forms on our teeth. These bacteria have quite the sweet tooth. They get the energy they need to live by consuming sugars in the foods you eat. The problem is that when they consume sugars, they produce acids that eat away at the very teeth they call home. The result: cavities.

Luckily, our mouths produce saliva. Saliva does a good job of counteracting the acids that the bacteria produce as they dine on the sweet stuff. It literally washes away the acids.

Chewing gum is a great way to get your mouth watering and your saliva levels up. So the act of chewing gum does tend to fight cavities. But if the gum contains sugar, it’s going to undermine the cavity fighting. So gum that’s good for the teeth is sugarless.

Most sugarless gums are sweetened with one of the following nonsugar sweeteners: maltitol, mannitol, sorbitol or xylitol. Xylitol is considered to be the best for dental health. Nonsugar sweeteners may also directly suppress the bacteria in dental plaque that cause cavities. This is particularly true for xylitol, which kills one group of bacteria that is the main cause of cavities.

But if you go in search of a gum that’s sweetened with xylitol, you’ll come back empty-handed. The brands we’re all familiar with – such as Dentyne or Trident – are sweetened with the other nonsugar sweeteners. Even when the package brags about xylitol, it’s often third, even fourth, down on the list of sweeteners.

Be aware that nonsugar sweeteners sometimes cause bloating, diarrhea or flatulence. Sugarless gum of any kind is better for your teeth than the sugary stuff. But we may not be getting the full benefit from the popular brands because of the type of sweetener that’s used.