Healthy Diet, Healthy Smile?

by Katelyn Castro

“Take care of your teeth when you get older because this is not fun,” the man said to me, pointing to his mouth. I was standing beside him at the Tufts Emergency Dental Clinic while the dentist explained his treatment options: a root canal or a tooth extraction. Despite the man’s best efforts to hold onto his tough persona with his leather jacket and tattooed crossed arms, I couldn’t help but notice his teary eyes as he sat in excruciating pain. Considering a root canal would cost him over a thousand dollars out-of-pocket, he settled for a tooth extraction, leaving him with 8 missing teeth at the age of 36.

I never realized the serious consequences of poor dental hygiene until I spent some quality time with dentists and dental students during my three-week dietetic rotation at the Tufts University Dental School of Medicine. Sometimes we take for granted all that our teeth do for us. Without them, we probably would not be able speak clearly, enjoy food, or even smile without receiving a funny look from someone. I don’t know about you, but I would like to keep my teeth as long as possible, please!

If you have ever been to the dentist, you’re probably familiar with the common dental hygiene recommendations: brush twice a day, floss at least once a day, and visit the dentist every six months. But beyond these basics, eating habits also play an important role in oral health. Sure, soda and candy may be the famous offenders causing cavities, but the research linking diet and oral health is much more extensive than this.

How Do Cavities Form?

In case your dentist hasn’t given you a lecture recently, let’s start with a quick science lesson on cavities. Like probiotics in the digestive tract, some bacteria in the mouth are considered “good bacteria” because they aid in digestion and protect teeth and gums. However, some strains of bacteria in the mouth are “bad bacteria.” These are the main culprits contributing to cavities. Whenever we eat a food or drink containing carbohydrates, they are broken down into sugars, which bad bacteria in the mouth feed on, creating acid as a by-product. In the dental world, this reaction is commonly known as an “acid-attack,” beginning within 20 seconds of eating or drinking carbohydrates and lasting up to 20 minutes. The acids can erode enamel, the tooth’s hard outer layer, dissolving minerals in a process called demineralization.

Repeated cycles of “acid-attacks” can spread tooth decay from the hard outer enamel into the softer dentin layer, with severe cases affecting roots and sensitive nerves. Cavities progressing to these later stages can be extremely painful, increasing sensitivity to hot and cold foods, and eventually leading to tooth loss.

Fortunately, saliva naturally fights tooth decay by helping to wash away food and replenish teeth with calcium and phosphorus in a process known as remineralization. Flossing, brushing, and using fluoridated toothpaste also protect against cavities by clearing plaque, making the mouth less acidic, and adding fluoride back to teeth.

NIDCR Tooth Decay Process


However, some eating habits can counteract the cavity-protective efforts of saliva, flossing, and brushing. Certain eating habits can contribute to tooth decay by promoting bacterial growth and the tooth decay process. Other food choices may prevent against decay and even reverse the process through remineralization. Although a healthy diet generally parallels healthy teeth, you may be surprised to find that even some healthy food choices could harm your teeth if you’re not careful.

Here are some steps you can take to make sure your eating habits are also keeping your pearly whites healthy:

1. Steer clear of sticky, starchy, and sugary snacks.

Believe it or not, starchy foods like potato chips or pretzels can be just as harmful to your teeth as sweets. These starchy foods are easily broken down into sugar in the mouth, leading to the same decay process as sweets. Sticky foods like lollipops, caramels, hard candies, and even dried fruits are the worst culprits because they not only promote bacterial growth but also adhere to teeth more, causing greater acid damage.

Nutritionally, most sticky, starchy, and sugary snacks have one common characteristic: they are filled with refined carbohydrates. These types of carbohydrates are stripped of important nutrients like fiber, vitamins, and minerals, making them less optimal than whole grains. Refined grains are also more rapidly absorbed in the blood, which can cause blood sugar spikes, increase appetite, and promote inflammation overtime, according to research. While dried fruits are higher in fiber than refined grains, they’re also a concentrated source of sugar, which may be harmful for teeth and overall health if consumed in excess.

Examples of sticky, starchy, sugary snacks to limit:

  • Hard candies, gummies, taffies, cookies, cake, raisins, and other dried fruit
  • Crackers, white bread, white pasta, potato chips, pretzels
  • Soda, fruit drinks, sports drinks, energy drinks

2. Be mindful of when you’re eating carbohydrate-rich foods.                                                                                                                         

According to a review of observational studies, the frequency of sugar intake was found to be more strongly associated with cavities than the quantity of sugar consumed. While this research does not suggest that binging on sweets and other carbohydrate-rich foods is the solution, the findings call attention to the potential effect of the frequency of carbohydrate-rich foods on oral health. Frequent snacking or grazing gives bacteria greater opportunities to feast on carbohydrates and gives acid more time to erode and demineralize teeth. Repeated acid attacks make it harder for saliva to do its job of neutralizing the mouth’s acidic environment and restoring important minerals in teeth. Enjoying your favorite carbohydrate-rich foods as part of a meal cannot only lower risk of cavities, but also make you more mindful and satisfied than grazing mindlessly on snacks or drinks throughout the day.

Here are some ways to keep snacking on carbohydrate-rich foods to a minimum:

  • Drink sweetened drinks (coffee, tea, juice) with meals, instead of sipping over a few hours
  • Eat your favorite starchy snacks (chips, pretzels, crackers) with meals, not between meals
  • Enjoy in your sugary cravings (cookies, cake, ice-cream) right after dinner, not late at night
  • Consider lower carbohydrate options for snacking (see below)

3. Opt for dairy and other healthy protein sources.

Unlike carbohydrates, protein and fat do not break down into sugars so they don’t promote bacterial growth or tooth decay. While dairy foods like milk, cheese, and yogurt have some natural sugars called lactose, they are also great sources of protein, calcium, and Vitamin D. With the synergistic role of calcium and vitamin D in bone health, dairy has been found in studies to have a protective effect on cavities through remineralization.

If you’re not a fan of dairy, don’t fret! Fish, poultry, eggs, beans, and edamame are also examples of healthy proteins that may help to strengthen and remineralize teeth because of their high phosphorus levels. Nuts and seeds can also be protective against cavities, providing another source of fiber, vitamin D, and calcium. The crunchiness of nuts and seeds can also stimulate saliva when chewing, naturally cleansing the mouth and flushing away food debris.

Incorporating more lean proteins and healthy fats into your diet could not only improve oral health but also bone and heart health. Choosing dairy and healthy protein sources as snacks (i.e., string cheese, yogurt) can help to offset the potential negative effects of carbohydrates on decay while also creating a more balanced plate.

Examples of dairy and healthy protein foods to include to your meals and snacks:

  • Dairy: string cheese, yogurt, milk, fortified soy milk or almond milk
  • Lean proteins: eggs, chicken, turkey, salmon, sardines, tuna, beans, edamame, tofu
  • Healthy fats: almonds, peanuts, cashews, pumpkin seeds, chia seeds, avocado

4. Snack on fruits and veggies.

Like nuts, high-fiber fruits and vegetables can cleanse teeth and stimulate the flow of saliva. Although fruits contain natural sugars called fructose, they are also high in fiber and water, providing a less concentrated source of sugar, which makes them a superior snack choice for your teeth and overall health. Fruits and vegetables also have an array of vitamins and minerals including vitamin A, vitamin C, vitamin D, and calcium, which collectively help to heal gums and strengthen teeth.

High-fiber fruits and vegetables to enjoy:

  • Apples, watermelon, strawberries, pears, plums, peaches, kiwis
  • Carrots, celery, cucumbers, broccoli, leafy greens, bell peppers

5. Don’t Let Acid Wear Away Your Teeth.

In addition to the acid produced from carbohydrate digestion, acidic foods and drinks also lower the pH of the mouth, demineralizing tooth enamel directly. When acidic foods and drinks are also high in sugar, their effect on oral health and overall health can be even more concerning.

However, the frequency of acidic foods can also make a difference. As the famous Stephan Curve demonstrates, the more time your mouth stays in an acidic state, the more harm acid can do to teeth. So, if you can’t break your relationship with Diet Coke, wine, or lemon-infused water, try sipping these drinks at meals instead of throughout the day. Also, try using a straw so teeth are less exposed to the acid and rinse your mouth out with water after having acidic foods or drinks.

Acidic foods and drinks to limit:

  • Soda (regular and diet), sports drinks, fruit juices and drinks, wine, beer
  • Flavored water, fruit-infused water (i.e., lemon, lime), seltzer water, tonic water, and other carbonated beverages
  • Lemons, limes, fried foods, high-fat meats, condiments (vinegar, soy sauce, mayonnaise)

6. Water Can Do Wonders for Your Teeth.

Drinking enough water throughout the day may the simplest, yet most important step you can take to prevent cavities. Sipping on water after meals and at snacks helps to wash away bacteria and neutralize the pH in the mouth. Since people with diabetes or people taking certain medications can experience dry mouth, a condition called xerostomia, drinking plenty of water can be especially important to reduce risk of tooth decay. Fluoridated water provides extra protection because the fluoride strengthens teeth by reversing demineralization. According to the American Dental Association, fluoride in community water systems (tap water) prevents at least 25% of tooth decay in children and adults. In fact, the Center of Disease Control and Prevention has identified community water fluoridation as one of the ten greatest public health achievements of the 20th century. Wondering if your tap water is fluoridated? You can check the fluoride levels of tap water in your community using this website.

Tips to get your fluoride fix:

  • Drink fluoridated tap water if available in your community, instead of bottled water
  • Filter tap water if concerned with contaminants in community water system (most commonly used water filters like Brita will not remove fluoride through filtering)
  • Use fluoride toothpaste and/or mouthwash
  • Consider talking to your dentist about taking a prescription strength fluoride toothpaste if you’re at risk of tooth decay

Bottom Line

Fortunately, most healthy foods are also healthy for your teeth. Fruits, vegetables, dairy, lean proteins, nuts, and seeds all make up part of a healthy diet, while also supporting healthy teeth. However, being mindful of how frequently your sipping and snacking on carbohydrate-rich foods and acidic foods and drinks may keep you from getting cavities in the future. Of course, brushing, flossing, and visiting the dentist regularly are also high on the list of priorities for good oral hygiene. While these healthy habits may seem trivial at a young age, let’s all learn from the poor man I met with 8 missing teeth at the age of 36; take care of your teeth now so that you can smile, eat, and enjoy food later in life.

Katelyn Castro is a first-year student in the DI/MS Nutrition Program at the Friedman School. She is a food science geek who loves experimenting with new food combinations in the kitchen.

The Friedman Sprout is a monthly student run newspaper that aims to serve the student population at the Friedman School of Nutrition Science and Policy, prospective students, and alumni. Our mission is to report on newsworthy information that affects the Friedman community including nutrition research, food policy, internship and volunteer opportunities, as well as school events. Our editorial slant is that of sustainability in food and nutrition.

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