Can strawberries whiten your teeth?

Can strawberries naturally whiten your teeth?

Can strawberries naturally whiten your teeth?

I was linked to this page by a friend, which essentially says that strawberries can whiten teeth. I have heard of this before- I remember as a kid my friend and I would take a bite out of our strawberries, and rub the fleshy part over our teeth. Repeat for every strawberry in the punnet until we finished all of them. I didn’t see any immediate change in my teeth so I stopped doing it- but perhaps I should have continued?

A quick bit about the structure of the tooth: there are four different types of tissue: enamel, dentin, pulp, and cementin. Enamel is the outside layer and thus the layer we see. It is naturally white or pale yellow and semi-translucent.

The four different tissue types in the tooth.

The four different tissue types in the tooth.

Tooth discolouration can happen from either the outside or the inside.

From the Outside:

The enamel can be stained by various food and drink in our diet, including wine, coffee, and tea. This is a superficial stain, where the colour from the food or drink is stuck onto your teeth. Have you ever left coffee in a cup for a day, emptied it and found your beautiful white coffee cup now has this ugly brown stain on it? That’s exactly what happens to your teeth.

From the Inside:

Because enamel is semi-translucent, dentin (the layer right underneath the enamel) plays an important part in tooth discolouration.

The dentin can become discoloured in a number of ways:

  1. Excessive fluoride use as a child. When you’re young, the protective enamel is not fully formed yet, so the fluoride affects the dentin and can cause damage. When you’re older and enamel has fully developed, this is not a problem.
  2. Tetracycline antibiotic exposure under 8 years old (including in the womb if your mother used it when carrying you).
  3. Trauma to your baby tooth that has also caused damage the permanent tooth (for example, if you fell and hit your baby tooth on something hard, it could hit the permanent tooth sitting above it, causing permanent damage that can be seen when it erupts later on).
  4. Trauma to your permanent tooth, causing bleeding into the dentin

Strawberries and tooth whitening- where did that come from?

Strawberries contains malic acid, which is the ingredient that is meant to buff away stains on tooth enamel. Note that this claim only involves discolouration from the outside. If the discolouration is from the inside, then this can’t be fixed and you may need to see your dentist about this. I believe the only treatment is to cover the discoloured tooth with a veneer, essentially covering it with white porcelain.

As for extrinsic discolouration, says you can mix a mashed up strawberry with a bit of baking soda and apply it to your teeth.

In my searches through scientific papers, the search terms “malic acid, teeth” or “strawberry, teeth” only come up with papers that warn of the erosive properties. Any kind of acid can cause tooth enamel decay, such illustrated by these studies. Note that these studies are all done in vitro, meaning that a researcher is using extracted teeth, placing them in an drink solution for a certain time (10 or 20 minutes) per day over a few days. That is totally unrealistic of what the exposure time to these acids are when you’re drinking or eating.

This study is a bit different. The authors constructed enamel slabs, placed it in a strawberry smoothie for two minutes, and then had people wear them around in their mouth (this study is called in situ, meaning that the enamel is in it’s natural place, in the mouth). This study showed that the strawberry smoothie (they also tested a banana smoothie) can potentially cause tooth decay, but not nearly as much as a cola drink.

Forget strawberries and tooth whitening. Just eat them instead!

Forget strawberries and tooth whitening. Just eat them instead!

From these studies, I conclude that you shouldn’t try to whiten your teeth with mashed up strawberries. The seeds can scratch at your tooth enamel, and malic acid can also cause damage.

Of course, these studies are mainly done by dentists and oral hygienists. You could argue that these people have an incentive to publish results that disprove natural remedies to keep up the professional teeth whitening services in business. That’s a whole different topic though

Have you ever tried to whiten your teeth with strawberries? Was it successful at all? Let me know!


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