How Sugar Indirectly Causes Cavities

Does Sugar Cause Cavities?

Yes. Sugars feed the harmful bacteria in your mouth which process those sugars into acids that slowly cause cavities in your teeth. Every reasonable dentist and researcher agrees that sugar is horrible for your teeth. However, the details are more complex.

The balance of bacteria in your oral microbiome heavily influences the rate of tooth decay, and your oral hygiene routine can prevent most tooth decay altogether. Sugar consumption is not the direct cause of cavities in your teeth, rather sugar sets off a chain reaction which we will discuss below.

Keep reading to learn everything you need to know about sugar’s correlation with cavities. Let’s turn that sweet tooth into a pearly set of healthy teeth.

Setting the Stage: Your Oral Microbiome

Your oral microbiome is the balance of bacteria in your mouth, on your teeth, and covering your tongue. These bacteria are largely beneficial, but too many of any good bacteria becomes a bad thing.

There are a few strictly harmful bacteria which largely contribute to cavity formation — namely Streptococcus mutans and Streptococcus sobrinus.

Acids from these bad bacteria constantly demineralize your dental enamel, stripping away the healthy surface of the tooth.

However, your saliva contains minerals like calcium and phosphate which constantly remineralize your teeth. Unfortunately, your oral microbiome and natural remineralization cannot keep up with a high-sugar diet. Sugar not only feeds those bad bacteria, but it makes your oral microbiome more acidic, lowering the pH in your mouth.

What Is Tooth Decay Really?

Tooth decay (AKA cavities or dental caries) is the most common noncommunicable disease in the world. It constitutes 5%-10% of industrialized countries’ healthcare spending.

Tooth decay occurs when bacterial plaque on your teeth consumes carbohydrates (including sugar) and secretes acids. These acids eat away at your tooth enamel and eventually your dentin (the layer below the enamel). The process of tooth decay can be accelerated when your oral microbiome is out of balance.

What is the most common cause of tooth decay? Tooth decay is most commonly caused by a combination of oral bacteria, high consumption of sugar, and poor oral hygiene.

Symptoms of tooth decay include:

  • Toothache
  • Tooth sensitivity, especially when eating or drinking something cold or hot
  • Bad breath (halitosis)
  • Bad taste in your mouth
  • Brown, gray, or black spots on teeth
  • Cavities

What are cavities? Cavities are pits or holes in the hard outer surface of teeth. If left untreated, cavities can lead to more complications, including:

    • Chronic pain
    • Swelling around tooth
    • Tooth abscess (tooth infection)
    • Chewing problems
    • Cold or hot sensitivity

Sugar Feeds the Wrong Bacteria

Sugars feed the bad bacteria in your oral microbiome. That includes all sorts of sugars: carbs in bread, fructose in fruits, lactose in milk, etc. However, sugar alcohols and artificial sweeteners do not feed the bacteria on your teeth and in your oral cavity.

When sugars feed the bacteria in your mouth, those bacteria excrete acids which eat away at your dental enamel. When acid wears down your tooth surface, cavities (pits in your teeth) slowly form.

Consuming sugary drinks or eating sugar foods is bad for your teeth. The higher your sugar consumption, the higher your risk of cavities.

Dental probiotics may support a healthy oral microbiome, which can help slow or prevent tooth decay.

Dietary Changes to Avoid Tooth Decay

Avoid sugar. That’s the basic dietary change you need to make to prevent tooth decay, but here are more detailed dietary change suggestions:

    • Don’t drink soda. Sugary soft drinks are filled with simple sugars which harmful bacteria love. Diet sodas may not contain sugar, but they are acidic and do stain your tooth surface, so they’re still not great for your teeth. When you do drink sugar-sweetened beverages, use a straw to limit exposure of the soda to your teeth.
    • Avoid bread. Bread is made up of carbohydrates, which are just sugars that feed the harmful bacteria on your teeth, just like sugary foods or hard candies.
  • Replace high-sugar snacks with healthy snacks. Instead of sticky snacks that are high in sugar (including natural sugar), opt for snacks that promote a healthy oral microbiome, such as crunchy celery, apples, carrots, low-carb yogurt, calcium-rich nuts, and low-sugar dark chocolate.
  • Eat vegetables which promote saliva production. Crunchy veggies increase the saliva in your mouth, which is great for your oral health. Saliva helps wash out plaque, acidic substances, and food particles on or in between your teeth which could otherwise contribute to tooth decay.
  • Drink plenty of water. Not only does water wash out acids and food particles like saliva, water also hydrates your mouth (preventing dry mouth) and hydrates your body (preventing all the complications that come with dehydration).
  • Chew xylitol sugar-free gum. Xylitol is a low-calorie sugar alcohol that is proven to support a healthy oral microbiome. This handy sweetener does not feed the bad bacteria in your mouth, and it may even slow the rate of tooth decay. (Do not let any dog eat anything with xylitol in it. Xylitol is great for humans, but canine digestive systems cannot process it, so it could be deadly to your pup.)

Dental Hygiene Reminders

How do you stop sugar from damaging your teeth? If you’re concerned about the effects of sugar on your teeth, start limiting your sugar intake. Meanwhile, good oral hygiene is essential in the prevention of tooth decay. Remember these tips to stop cavities from forming:

    • Brush your teeth twice a day, but not right after a meal. If you brush right after eating or drinking, you might rub harmful acids from that food or drink into your teeth, weakening your tooth surface. Not brushing increases the risk of dental plaque turning to tartar which is harder to remove and is a big factor in tooth decay and gum disease.
  • Aim your brush towards your gum at a 45° angle. Use gentle circles to safely disrupt the bad bacteria on your teeth without damaging your gums or tooth surface. Angling your brush removes the plaque buildup right underneath your gum line that contributes to tooth decay.
  • Use a good toothpaste. We recommend Revitin — an all-natural, fluoride-free, prebiotic toothpaste full of vitamins and minerals that support your whole mouth.
  • Avoid alcohol-based mouthwash. Alcohol dries out the mouth, and dry mouth promotes harmful bacteria proliferation. Rinsing your mouth out with water or certain all-natural blends can help prevent tooth decay and gingivitis.
  • Flossing daily removes interdental plaque. Your toothbrush probably can’t reach that plaque in between your teeth. Flossing prevents interdental bacteria from lingering in those hard-to-reach places, where the harmful bacteria may form cavities.
  • See your dentist at least once a year. Twice yearly checkups are better. Your dentist will notice early stages of dental cavities before you can. A good dentist can identify problems that cause tooth decay or issues with your dental care routine.

Need More Information?

Maybe your situation calls for an individualized solution. Plenty of functional dentists and doctors across the nation can give you more information on your dental health that conventional doctors would shy away from.

If you’re looking for holistic care for your unique situation, schedule an appointment with Rejuvenation Dentistry. We offer biological, conservative, integrative, holistic treatments for all sorts of oral conditions, as well as whole-body issues that start in the mouth.


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Dr. Gerry Curatola is a renowned biologic restorative dentist with more than 40 years of clinical practice experience.

He studied neuroscience at Colgate University and attended dental school at the New York University (NYU) College of Dentistry where he now serves as Adjunct Clinical Associate Professor in the Department of Cariology and Comprehensive Care.