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Dental Cavities. How does your diet affect your teeth?

Dental Cavities. How does your diet affect your teeth?

how does your diet affect your teeth

To prevent dental cavities and dental erosion, it’s important to understand the role of your diet – that is, what you eat and how often you eat it.

In ancient cultures such as those of Greece, India, China and Egypt it was widely believed that a “tooth-worm” tunnelled a hole through a tooth and would hide underneath the tooth surface. It would go on to cause a toothache by wriggling around, and the pain subsided once the worm rested. Today, however, after centuries of research, it is well established that dental cavities and tooth erosion are directly related to dietary factors. Dental decay is essentially caused by the breakdown of the tooth surface, primarily from two sources:

  1. plaque bacteria
  2. a sugar-rich, acidic diet.

Plaque bacteria

Plaque is a complex community of bacteria appearing as a sticky, tooth- coloured film that grows on our teeth every day. To flourish and grow, the plaque bacteria require food in the form of sugars – or more specifically, carbohydrates. When the bacteria are exposed to carbohydrates they are able to convert the sugars from the foods and drinks you consume into acid. It is this acid that attacks the teeth, breaking them down and starting the decay process. So it’s important to remove plaque bacteria through good oral hygiene and a good diet.

Sugary and acidic foods

When sugary and acidic foods and drinks are consumed, not only is acid produced by plaque bacteria but the mouth will shift to a more acidic environment – with a raised pH level. A sugary and acidic environment is perfect for the plaque bacteria to thrive. Saliva plays a vital role in cleansing food from the teeth and bringing the pH level back to normal. It takes the saliva around 20 to 40 minutes to buffer the mouth back to a normal, non-acidic and safe level.

Our mouth is the gateway for food and nutrients to enter our bodies. What and how often we eat and drink can affect not only the health of our bodies but also that of our mouths. It is important to have a healthy, balanced and varied diet, but it is also important to know that some foods and drinks are less tooth-friendly than others.

It is well understood things like fizzy drinks and chocolate are bad for our teeth. These foods and drinks contain sugar. Sugar propels the plaque bacteria in our mouth into a feeding frenzy, allowing them to produce acids that will break down the teeth and lead to dental cavities. Most foods and drinks contain different forms of sugar; it’s how we consume them, and how often, that is of most importance. Lollies, chocolate, muesli bars, even packet chips all contain added and processed sugar. Fizzy drinks, fruit juices, cordial, energy and sports drinks are all high in acidity and sugar. These should all be limited.

Sticky foods

Foods that are sticky are more likely to stay on our teeth for longer. The obvious culprits include chewy lollies such as roll-ups and Minties. However, even some things that sound healthy – like dried fruit and honey – can stick to the teeth for some time, increasing the risk for dental decay. Instead of snacking on dried forms of fruit, reach for fresh fruit varieties or confine these foods to meal times.

Dental erosion is the irreversible loss of the tooth surface layer due to acid exposure. Dental erosion thins the strong, protective outer enamel layer of the teeth and in turn increases the chance of decay. Dental erosion makes the teeth appear thin and translucent, and it can also make the teeth very sensitive and uncomfortable. Foods such as lemons, limes, tomatoes and vinegar (particularly in salad dressings), as well as drinks such as those mentioned above, all contribute to dental erosion. Often people will choose to drink fruit juices as a healthy option to water, but fruit juices are high in acidity and sugar. It is best to eat fresh fruit, rather than drink juices, to gain the benefits of fibre and extra nutrients. Again of significance are not only the amount but more importantly the frequency of how these foods and drinks are consumed.

It’s not all bad news. There are many foods (and pure juices made from these) that are recommended to reduce the risk of dental cavities and erosion. These include:

  • fresh fruits and vegetables such as carrots, apples, celery and cucumber
  • nuts and legumes
  • dairy foods, including cheese, low-fat & low-sugar yoghurt and plain milk
  • eggs
  • white and red meat
  • seafood.


  • Eat sugar-containing foods only occasionally. If consuming these foods, try having them with or around meal times.
  • Drink acidic and sugary drinks only very occasionally. When consuming them, do so with meals and through a straw.
  • Water is best to promote healthy saliva and cleanse the mouth after meals.
  • Reduce snacking on sticky and sugary foods in between meals. Instead snack on tooth-friendly foods.
  • Rinse your mouth with water after meals and snacks.
  • Avoid sugar with tea and coffee.
  • Avoid eating before bed, particularly sugary, sticky foods.
  • Chew sugar-free gum after snacks and meals to stimulate saliva flow and clear food from the teeth.

In a nutshell, always have regular dental check-ups and cleans with your dentist and dental hygienist and be sure to have conversations with these dental professionals to maximise your oral health education and reduce your risks for dental cavities and dental erosion.

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