What foods are good (and bad) for your teeth

As more and more people are now taking better care of their bodies, health, wealth, and being more mindful about the planet, they are also asking how do we take better care of our teeth/mouth. At Duddingston Park we love hearing this question because it means our patients really care and want to make small improvements that will last a lifetime.

This article will explain how teeth decay and how to prevent the teeth from decaying. We won’t spend much time talking about gum health, that’s for another day.



Tooth decay (caries) is when bacteria from a colony (biofilm) on teeth is slowly destroying the teeth from the outside in, leading to loss of tooth structures (enamel/dentine/root). Depending on the stage of the decay it can be extremely painful, slightly annoying, or not noticeable at all. For decay to occur, 4 things NEED to be present.

  • Bacteria
  • Tooth Structure
  • Sugar
  • Time

Bacteria form a plaque (think about the stuff that forms around a sink plug!) and this produces acid, which slowly dissolves the Tooth structure over Time. The bacteria eat certain types of Sugars which allow them to grow. If this process is allowed to occur, decay will begin and once it starts it is hard to stop. In fact, once decay gets past a certain point, the only option is to have dental treatment. In this case, prevention is definitely better than cure.




The sugar element comes from the food we eat. Most foods contain some type of sugar. These can be broken down into these 4 types.

  • Glucose.
  • Fructose (a.k.a. fruit sugar)
  • Sucrose (a.k.a. table sugar)
  • Lactose (a.k.a. dairy sugar)


The first 3 (glucose, fructose and sucrose) are also known as NMES (non-milk extrinsic sugars), which basically means that they are not found in milk. They can be added to foods, or they may come naturally from the fruits we eat. NMES are fermentable by the bacteria in our mouth, which means they lead to acid production, which leads to decay. Eliminating these from our diet will help reduce decay. Although this is hard – so we have a few tips in the next section to help with this.

Lactose is sugar that comes from milk or other dairy products. This is not fermentable by the bacteria in our mouth. Which means no acid and no decay. Happy days!! In fact, milk is so good it actually neutralises the acid caused by other foods, further preventing decay. And there is more milk that also contains vitamins and minerals including fluoride and calcium both help to strengthen teeth especially in children with developing adult teeth.

How to avoid NME’s?


YOU CAN’T!!!!!! Seriously, it’s that simple, it can’t be done. Even with a healthy and balanced diet, you will have fruits and vegetables that contain NMES. The aim of the game is not to avoid them, but to be smart about them.

The more times you eat a day, the more often your teeth will take a hit. So limit the number of times you eat. The majority of food consumed is slightly acidic, bacteria love this. The more acid the more chance of the decay process starting (also the more acid the more minerals your teeth lose). Around 30 minutes after you eat food, your mouth will naturally neutralise. So this gives us options, we can;

  • Manage the number of times we eat a day (limit to 3 meals a 1 snack) 4 hits per day
  • Neutralise the mouth after we eat
  • Concentrate on food with that is less acid.

Eating 4 times a day to some sounds easy, to others (including me) sounds hard. This includes drinks, they are usually more acidic than food. To be honest you don’t have to only eat 4 times a day but to start to reduce the risk of decay avoid snacking.


When I was a kid, my Dad used to give me Werther’s originals toffee’s. We would go on a walk on a Sunday, and he would give me 1 toffee every 10 minutes, over the space of around 3 hours. He believed that spacing it out would be better for me, with less sugar in one go. For my behaviour it probably helped, but for my teeth, it was a disaster. My teeth were bathed in sugar and acid for 3 hours!!! Now we know that that is the perfect recipe for decay.




How do we reverse this situation? There are a few ways that are possible but not always practical.

For most, the quickest and easiest way to neutralise your mouth is with chewing gum that contains products like sorbitol or xylitol (not bubble gum). These products are alkaline (opposite of acidic) and balance the level acidity (ph) in your mouth. In fact, it can bring it back to comfortable levels within 10 minutes. Fantastic!!


(From a reader: “Mate, I have read some of your articles and in one of them you said don’t chew gum to avoid jaw problems – which one is it?”)

(Answer: Thanks for reading and paying attention. This statement is correct and a bit annoying. If you have jaw problems, such as clicking, locking, and popping chewing gum regularly is not a good option. Actually, it should be avoided. This is the reason I do not chew gum. I end up with a sore jaw. Keep reading and there are some more pointers)


Mouthwash, after you eat, is a fantastic way to neutralise the pH in your mouth. It also flushes out so extra bit of food. In a lot of cases it may be better than brushing as brushing is harsh and if your mouth is acidic it can lead to removing the top layers, increasing sensitivity or tooth wear.

Mints containing xylitol and sorbitol. This acts the same as chewing gum, without having to over work your jaw.

Milk is our teeth best friend, having a glass of milk after eating will do the same as above to a lesser extent.



So I have talked a lot and not actually mentioned any foods, but the name of this article is what foods are good for my teeth. If I didn’t explain all the stuff above, some of what I am going to say will make very little sense.

Foods to avoid


When it comes to teeth, we can split foods and drinks into 3 categories: acidic, sugary or both. Below are some examples to watch out for.

Sugary; Sweets (duh), cakes, certain breakfast cereals, breakfast bars, granola, berries (strawberries, raspberries etc), dried fruits such as raisins

Acidic: Wine, citrus fruits, diet carbonated drinks (all of them),

Both (I’ve included a few of my pet hates, especially for kids):

Tomato Ketchup (this is one of the worst offenders and a MASSIVE reason why kids have decay), fruit shoot, energy drinks (athletes often suffer from decay and sensitivity and this is a major factor!), Tang-fastics (one of my personal guilty pleasures), lollipops, full-fat carbonated drinks especially fruit based such as lemonade

Top Tip: if you read this and want to make a couple of simple changes that will impact you and your family, start with swapping out the ketchup for the new ½ sugar products and instead of fruit shoot give them weak diluting juice. Robinsons for example have a product called squash that allows you to turn any glass of water into a fruit drink. Using this can serve as a good alternative to a fruit shoot.


Does any food have no NMES?


Some food actually contains either non or very few NME’s, however, this is where it gets confusing as some of these foods and drinks may not be so good for you!

Eggs, Milk, cheese all contain very few or no NME’s. As does potatoes, sweet potatoes, carrots, lettuce, cabbage, peas and other green vegetables. From a sugar perspective, most vegetables contain few NME’s.

Crisps usually contain very few NME’s, as does vodka and gin. Just because they don’t contain NME’s does not mean they will be good for you!

This is why having a fully balanced diet, avoiding snacks, using chewing gum or mints and regular brushing and fluoride will all help to avoid decay and have few trips to the dentist.


Dr Abraham McCarthy

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