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You probably already know that sugar causes cavities, or dental caries. But the connection isn’t quite that direct. Understanding the mechanism can help with behavior modification to help prevent cavities.

How Sugar Leads to Cavities

Your mouth is part of your gastrointestinal tract—so just like the rest of your gut, your mouth has a microbiome too. And, just like elsewhere in the gut, the mouth can be a battleground between good flora and opportunistic flora looking to take advantage of weakened defenses.

In the mouth, the bad bacteria are primarily streptococcus mutans and streptococcus sorbrinus. They eat sugar—and what you feed, grows. As they digest sugar, they produce acid. This acid can demineralize the protective enamel on the teeth, leading to decay.

You might think refined sugars are the only ones that can set up this process, but alas — any sugar that breaks down into glucose in the saliva can have a similar effect, including healthier natural sugars like honey and maple syrup. The same goes for simple carbohydrates that turn to sugar when they reach the saliva: things like processed white bread, chips, crackers, and pasta, for example.

The same is not true of whole foods, though: whole starchy foods and fresh fruits combine their carbohydrates with fiber, which slows the release of the sugars into the bloodstream. This not only helps to stabilize blood sugar, but also keeps those sugars from affecting the oral microbiome.

How Your Body Can Heal Cavities

The body is designed to heal itself, and the teeth are no exception.

Saliva is rich in minerals necessary for remineralizing the dental enamel. With enough time between insults to the teeth, and adequate building blocks for repair, it is possible for cavities to heal.

How to Minimize Damage

Unfortunately, the standard American diet doesn’t leave a whole lot of room between sugar exposures for the saliva to complete the job. There’s a clear relationship between frequency of sugar exposure and development of dental caries.

Sugary beverages are also probably the worst dietary offenders for the teeth, just as they are for the rest of us, and for the same reason: they carry no fiber at all to slow the impact of sugar on the teeth or the bloodstream. Even one occasional sugary beverage carries a significant increased risk of losing 1-5 teeth.

But, if you must eat sugary foods or drink sugary beverages, it’s best to decrease the amount of time those foods spend in your mouth itself. A straw might be a better choice for consumption, to minimize the surface contact with the teeth. Likewise, sucking on hard candies or chewing taffy means more time for the sugar to be in contact with the teeth, leading to more acid production by the bacteria.

Also, anything that helps to stimulate saliva will also help with prevention of caries. This is one of the primary reasons sugar-free gum is recommended for dental health, particularly gum sweetened with xylitol.