Which sugars harm your teeth?

Which sugars harm your teeth?

by | 15 Jun, 2017 | Blog, Dental Decay, General Dentistry

Not all sugars are made equal. Can you believe that? And some are more harmful to your teeth than others. The important question is then, which types of sugar are the bad ones?

The official answer is “Fermentable carbohydrates”.

As we all know, we consume carbohydrates for energy but carbohydrates come in 2 main forms, namely the complex carbohydrates and simple (fermentable) carbohydrates.

Complex carbohydrates

or what we called Starch (e.g. found in potato, rice, corn, etc) get break down into simple sugar in our stomach and throughout our digestive system. Bacteria in your mouth don’t have the capacity to process this type of carbohydrates down and therefore they tend to be less harmful to your teeth.


Simple carbohydrates

or what we called Sugar is the one that bacteria can feed on in the process called fermentation. The bacteria digest sugar to produce acid, similar to what we see in a beer or wine-making process. The common simple sugars are glucose, fructose and galactose. We will look at these ones more closely.


Galactose is one of the two simple sugars formed when lactose breaks down, the other being glucose. It is commonly found in dairy products such as milk. Not as many bacteria have the necessary enzyme to metabolise lactose into simple sugars (galactose and glucose) and therefore it doesn’t accumulate enough to be harmful to our teeth.

Galactose is often found in dairy products


Fructose is a naturally occurring sugar found in fruits and vegetables. My patients often asked if having a lot of fruits a bad thing for teeth. When consumed in its natural form, it is said to be a good and healthy habit. As the documentary “The Truth About Sugar” demonstrated, each fruit contains enough fibre to prevent us from consuming too much sugar at any one time. Simply said, we would be full first. On the other hand, when the fibre is taken out of fruits, we can easily consume more of its sugary juice because we don’t feel full. So, I would recommend more of whole fruits and less of processed juice.

Fructose is found in fruits.


Glucose is the most common small building block of a bigger complex carbohydrates we called starch. This is usually only broken down when going through our digestive system and therefore has limited danger to our teeth. The real harm comes from consumption of glucose or small chain of glucose such as sucrose (table sugar) that is only made available from commercial processing. This is why “refined sugar” or “added sugar” are the things to watched out for and processed foods have plenty of it in order to enhance taste. It is interesting to note that historically, the rate of dental decay increased significantly after the industrial revolution that made sugar a widely accessible commodity.

Refined sugar, a sugar to watch out for

Knowing these facts, we can make healthier choices on what to drink or snack, because not all sugars are made equal.

To your healthy smile.
Dr. Supa
Supa Dental, Melton.