If you want to prevent cavities, how often you eat can be just as important as what you eat. That’s because food affects your teeth and mouth long after you swallow. Eating cookies with dinner will do less harm to your teeth than eating them in the middle of the afternoon as a separate snack. Of course, overall poor nutrition can contribute to periodontal (gum) disease and can have other long-term effects on your mouth. Learning how food affects your oral health, long term and short term, is the first step toward mouth-healthy eating.

Changes begin in your mouth the minute you start to eat certain foods. Bacteria in your mouth make dental plaque become more acidic, and the acid begins the process that can lead to cavities.

How does this happen?

All carbohydrate foods eventually break down into simple sugars: glucose, fructose, maltose and lactose. Some foods, called fermentable carbohydrates, break down in the mouth, whereas others don’t break down until they move further down the digestive tract. It’s the fermentable carbohydrates that work with bacteria to begin the decay process and eventually destroy teeth. They include the obvious sugary foods, such as cookies, cakes, soft drinks and candy, but they also include less obvious foods such as bread, crackers, and cereals. Certain bacteria on your teeth use the sugars from these foods to produce acids. The acids dissolve minerals inside the tooth enamel in a process called demineralization. Teeth also can regain minerals in a natural process called remineralization. Saliva helps minerals to repair teeth and so does fluoride and some foods.

Dental decay begins inside the tooth enamel when minerals are being lost faster than they are being regained.

The longer food stays near the bacteria on the tooth, the more acids will be produced. Sticky carbohydrates, such as raisins, can do a considerable amount of acid damage. But other non-sticky foods can cause just as much harm because they can pack into the tooth crevices. Potato chips are a terrific example. Eat a handful of chips and see how long you have to work to get all the bits out from between your teeth. Teeth with a lot of crevices, such as molars, are more likely to trap food. That’s why they tend to have more decay.

To make matters worse, many of the unhealthy foods don’t just create acids but these acids stick around for the next half-hour.

Depending on your eating and drinking patterns, it’s possible for the bacteria to produce acid constantly. This can happen if you sip soft drinks or sweetened coffee throughout the day. Eating many small sweet or starchy snacks can produce the same effect. The resulting acid damage adds up, so decay is more likely. Studies have shown that those who eat sweets as snacks between meals have higher incidences of decay than those who eat the same amount of sweets with their meal.

On the brighter side, some foods actually help protect teeth from decay. That’s because they increase saliva flow and neutralize the acids produced by bacteria. This makes it less likely that the enamel will lose minerals. For example, aged cheese eaten immediately after other food helps buffer the acid.

Chewing sugarless gums also can help protect your teeth against cavities. Xylitol is an ingredient in some sugarless gums. This sweetener has been shown to reduce the amount of bacteria in the mouth. It also helps to buffer the teeth against the effect of acid. Most sugarless gums and sugarless candies increase the flow of saliva, which helps to protect your teeth against bacteria.

Like the rest of your body, your mouth depends on overall good nutrition to stay healthy. In fact, your mouth is highly sensitive to poor nutrition. It can lead to tooth loss, serious periodontal (gum) disease and bad breath.

The current and best guidelines for overall good nutrition was developed by the USDA, these guidelines can be found at www.mypyramid.gov.