Sugars: The Good and the Bad
You probably know that tooth decay results when the bacteria in your mouth release acids after consuming sugars. After you eat sugars, particularly the type of sugar known as sucrose, increased acid in your mouth begins to dissolve the enamel and dentin in your teeth, and you end up with cavities.
What are the Types of Sugars?
Modern diets include several types of sugars. Most of these are fermented by oral bacteria, producing acids that are harmful to teeth.
- Sucrose (commonly known as sugar)
- Glucose (released from starch consumption)
- Lactose (milk sugar) — Less acid is produced from this type of sugar
- Fructose (found naturally in fruit and also added to many processed foods)
Recommended intake of “free sugars” is no more than 10 teaspoons per day. Note that a can of soda contains over 6 teaspoons! Soft drinks are the largest source of sugar consumption in the U.S. In 2003, for example, Americans drank an average of 52 gallons of soft drinks. Average per capita consumption of all sugars in the U.S. was 141.5 pounds (64.3 kg) one of the highest levels in the world.
Sugar substitute xylitol (which is chemically similar to sugar but does not cause decay) can be part of a preventive program to reduce or control tooth decay. Chewing gum sweetened with xylitol stimulates saliva flow and helps protect against decay.
Sugars Released from Starches
Starches are foods like rice, potatoes, or bread. When you eat refined starches, such as white bread and rice, enzymes in your saliva release glucose. However, these foods have a lower potential to produce decay than foods with added sugars. When sugars are added to starchy foods, as in baked products and breakfast cereals, the potential for decay increases.
Less refined starches such as whole grains require more chewing and stimulate secretion of saliva, which protects from harmful acids.
The Case for Fruit
Fresh fruit has not been shown to produce cavities, so it makes sense to eat them instead of sugary desserts and snacks. Dried fruit is more of a problem because the drying process releases free sugars.