How Diet Affects Your Teeth

2713 pH Scale-01

But I brush my teeth twice a day and floss them daily!”

I get cavities very easily. It runs in the family… We have weak teeth.”

Sound familiar? This is something I often hear when I tell patients they have a new cavity or early signs of them. Because my way of thinking is generally based on no-nonsense, I will not speak nonsense to my patients and therefore will correct any nonsense coming from their mouth. What I will say immediately to the person thinking bad teeth are hereditary is that there is no such thing as hereditary bad teeth. What can be hereditary is

  • diet and lifestyle habits (sort of… at least until you get to decide yourself what to eat and drink and how often)
  • bacteria (but not exactly hereditary, the baby is born without bacteria in mouth and bacteria will be transferred into baby’s mouth normally from the parents)
  • genetic susceptibility to periodontitis (but this does not mean you are doomed to have periodontitis)
  • position and the shape of the teeth

But it is only the diet and lifestyle habits that can be easily changed by person himself to such that is more tooth-friendly. So what is tooth-friendly and what’s not? I will tell you but I cannot do that before I tell you little bit about bacteria first.

Bacteria – the Beloved Enemy

There are bacteria in everyone’s mouth and so there should be. The bacteria keep the soft tissues healthy. Every day the bacteria try to find hiding and breeding places from our teeth forming this sticky glue around them. Bacteria and this glue we call plaque.

We can live in peace with the bacteria if we remove it regularly from the surfaces of our teeth. It is beneficial also to remove it from the surface of the tongue. Brushing twice a day with an electric toothbrush and cleaning between the teeth once a day (the best tool for you to use between the teeth should be checked at the dentist – preferably by the dental hygienist) will prevent the bacteria causing problems like cavities and gum disease.

But if the bacteria can stay in place for longer period of time, there will be consequences. Let’s first think about how it will affect the gums around the teeth.

Healthy gums will start to get inflammation after three days of bacteria presence (there is some individual variation to this) because the bacteria will produce toxins amongst other things. For example if you do not clean between the teeth for four days, the chances are high for you to notice bleeding from the gums when you finally decide to clean them. The bleeding is always a sign of an inflammation in the gum (gingivitis) caused by prolonged bacteria presence. It is never a sign of you doing something wrong with the tool you use. So consider the bleeding as a reminder for you to clean between the teeth more regularly as gingivitis can lead to more severe and irreversible type of gum disease (periodontitis).

The bacteria also produce acids from the carbohydrates in your diet. This is called the acid attack. The acids will affect the teeth.

The acids that the bacteria produce from the carbohydrates will make the pH of the mouth drop below 5,5 and this will remove minerals like calcium from the surface of the teeth. It is called demineralisation. The saliva neutralises these acids bacteria produce and also it is the saliva that will try to restore the lost minerals from the enamel but it is slightly slow process and normally after 30-45 minutes of finishing you dinner/snack the job is done and the pH has risen above 5,5. This is called remineralisation.

The teeth can take only certain amount of demineralisation per day without getting cavities. Too much demineralisation combined with inadequate oral hygiene habits will most certainly lead to decaying. Sometimes very fast decaying.

Not Necessarily What You Eat, but How You Eat It!

So now you know that the demineralisation will begin when you offer carbohydrates to the bacteria in your mouth. There are carbohydrates in pretty much everything we eat. The juices, milk, fruits & veg, bread, cereals, honey, pasta, rice – they all have it. Sweets definitely have it. Even just one tiny grape will begin the demineralisation which will last the next 30-45 minutes before the saliva has neutralised the acids.



Teeth can take up to 5-6 of these acid attacks per day without getting decay. So if your eating habits include more than 5-6 meals/snacks/drinks with carbohydrates, you have a higher risk of getting decay. How fast the decaying is depends on your oral hygiene habits (plus some other factors like buffer capacity of the saliva but these details will only confuse you so let’s stick to the basics).

The worst you can do to your teeth is to snack every half an hour because this means the pH level that dropped when you began your session of snacking will never raise above the safe level of 5,5. So in the worst case scenario you might take e.g. cookie/fruit every half an hour from midday till you leave work around five to get you through the day. This means that you had a massive 5-hour-long acid attack in your mouth. If this happens often, it will definitely lead to decaying.

Sugar-Free Does Not Always Mean Tooth-Friendly

Soft drinks contain massive amounts of sugar. A 16 oz bottle of coke can have 13 sugar cubes (4g cubes). This is one reason some people switch to sugar-free soft drinks. Often people do not realise that the drinks that are better for the waist-line are still as harmful to teeth as regular soft drinks. The reason for this is the pH of the drink.


The lower the pH the more harmful it is to teeth. The low pH does not cause decay as such but it causes dental erosion which is as damaging as decaying is. Erosion on teeth means the surface of the tooth is loosing minerals as a result of an acidic drink making the enamel thinner. Here is the most important sentence to memorise:

The enamel does not grow back!

So it is very important to prevent any loss of tooth structure before you are in trouble with sensitive teeth, colour change of the teeth to yellow (thinning enamel allows the yellow dentin under it to show through), decaying (thin enamel decays quicker) and possibly imbalanced bite due to the loss of tooth structure. These problems caused by enamel erosion are very difficult and expensive to treat.

Do not think these things are not happening in your mouth. They are. I see it every day with more and more patients. Remember that the acidic drinks are not recommended to be consumed daily and when you do, consume them with a meal and drink tap water after you have finished eating and drinking. This will neutralise some of the acids.

Here are a couple of examples of the drink’s pH value:

  • cola drinks from 2,32 (Pepsi Max 2.74)
  • lemon juice 2,25
  • 7up 3,24
  • Ocean Spray Cranberry 2,56
  • strawberry Dasani 3
  • pure water 6-8
  • Red Bull 3,3
  • Full Throttle 1,45

Remember that the plain sparkling water’s pH is around 5. But if you add flavour to it with your soda maker the pH will drop close to 3 or even below it. So it is always better to choose the plain sparkling water than the flavoured one but it is worth noting that there is still a debate amongst us dental professionals whether the plain sparkling water is harmful to the enamel.

If you want to find out more about the pH value of the drinks, click here. And here is an article worth reading: The Washington Post: Why flavoured waters are bad for you teeth.

Vegan Diet and Erosion

Vegan diet in a nutshell means that the diet is devoid of all animal products, including meat, eggs and dairy. The vegans who base their diet on fruits and vegetables are at higher risk of developing dental erosion. The culprit for this is the acidity of the diet and lack of calcium in diet.

Patient Case

50-year-old lady came in to see me for the first time. She had been on a vegan diet for almost all her life. She started the day with a lukewarm water with a splash of lemon followed by a smoothie after which she brushed her teeth with a non-fluoride toothpaste. During the day she followed her vegan diet, drank herbal teas between the meals. In the evening she brushed her teeth again with a non-fluoride toothpaste.

The clinical findings:
The enamel of every single teeth was riddled with severe erosion. The fillings she had were protruding from the tooth as the tooth structure itself had dissolved around them. She had suffered from sensitive teeth and could not eat or drink anything too cold. The enamel of her front teeth were so thin that the colour of the teeth was yellow from the dentin showing through. The front teeth looked like the gremlin’s teeth due to chipping of the thinned enamel. She would need extensive rehabilitation of the occlusion and the aesthetics with crowns and fillings. Needless to say that the treatment would cost a small fortune.

What was the downfall of her teeth? Well, many factors contributed to this severe dental erosion:

  1. The combination of acidic diet and lack of calcium-containing products in the diet. It is advisable to combine acidic food with a dairy product. For example by adding natural yoghurt to your smoothie.
  2. The breakfast should include something you chew. Your saliva flow has dramatically decreased over night and it is chewing that will make the saliva flow again. If you drink something acidic when the mouth is dry (in this patient’s case lemon water and non-dairy smoothie) there is no saliva to protect the teeth. It is the saliva that neutralises acids and restores the minerals back to the enamel.
  3. Non-Fluoride toothpaste. Fluoride will work like calcium on the enamel. It will form even a stronger layer on the surface of the tooth than calcium and other minerals found on enamel. So when using only non-fluoride toothpaste, you are relying on your saliva to do the remineralisation. But like with this patient it simply was not enough to protect the teeth.
  4. Unawareness. Not knowing how our diet affects your teeth is the downfall of many. This patient had acidic vegan diet plus drinks that are highly acidic like water with lemon and the herbal teas.

Other Harmful Diets

There are new fashionable diets popping up all the time and I might not know all of them. But to name a few:

  • Juicing – everything is in a form of a juice. The problem with teeth: no chewing means no saliva to protect your teeth! No dairy-products.
  • Smoothie diet. The problem with teeth: no chewing or no dairy-products.

How to Protect Your Teeth from Your Diet?

  • If you decide to follow certain trendy diet, find out first how it will affect your teeth. Do not turn to Google if you are not able to tell the difference between fake health news and real, scientifically proven advice. Ask your dentist or hygienist instead.

    These fake health news -sites are very convincing. Even I almost started to believe in the nonsense they were writing when researching for this post. So be alert, trust the dental professionals who have many years of education that is based on science.

  • Think about your current diet. Does it include lots of acidic drinks or foods. You can find out the pH level of many foods and drinks from the internet.
  • Finish your dinner or snack to a slice of cheese. Chew it well. This will neutralise the acids and restore the calcium to the enamel (cheese is rich in calcium).
  • Finish your dinner or snack to a Xylitol. This will neutralise the acids after dinner. Two pastilles sweetened 100% by xylitol five times a day will also decrease a chance of decay. Want to find out more about xylitol, click here.
  • Use products like GC MI Paste Plus or GC Tooth Mousse to restore the lost calcium in your enamel. The GC Tooth Mousse can be used many times a day as it does not contain fluoride. The best time to use it is just before bedtime by applying pea-size-amount with e.g. cotton stick all over the teeth and leaving it overnight.
  • Use fluoride toothpaste twice a day and do not rinse your mouth after brushing. Just spit out.
  • Avoid fizzy drinks and juices. Only drink them at mealtimes and try to avoid daily consumption.
  • Avoid snacking. But if you do snack, remember that natural nuts are tooth-friendly snack.
  • Avoid alcohol or drink in moderation. Alcohol is always a risk to your teeth, mouth and general health. It is an acidic drink and the bacteria in your mouth will metabolise the alcohol into acetaldehyde which is carcinogenic in humans.

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