Curious Kids: why do we make saliva?

Why do we make saliva? – Lilia, aged 7.

Thanks for your great question, Lilia. I’m a dentist, so I know a bit about what’s happening inside our mouths, and I can tell you saliva is very important.

It helps us enjoy our food, it helps sores in our mouth get better, and it fights nasty germs – just to name a few.

But first, let’s look at how we make saliva.

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It comes from our salivary glands

Saliva is made in special pouches called salivary glands. These glands look like rows of water balloons that fill and empty into tubes called salivary ducts. As the balloon-like glands fill up, the saliva gets squeezed into the tubes, and then your mouth.

We have hundreds of little salivary glands dotted all around our lips and cheeks. We also have six big glands (made of hundreds of little glands) in our mouth that produce most of our saliva; four are under our tongue and one on each side of our cheeks.

Everyone produces different amounts of saliva, depending on how healthy you are and how much water you drink. In one day, you could produce enough saliva to fill more than a litre carton of milk. In one year, you could make enough saliva to fill two bath tubs. That’s a lot of spit!

Saliva’s super powers

Our saliva is mostly (99%) made of water, mixed with useful things like salts.

The ingredients in saliva are complicated, but that 1% is important. Saliva can help protect us against cavities (holes in the teeth) by washing our teeth with special salts. And because it’s slippery, saliva stops the bugs that create holes from sticking to our teeth.

If you have a cut inside your mouth or lose a baby tooth, saliva can help you heal faster. It can also fight most nasty germs and makes it difficult for bad bacteria (or bugs) to stick and grow in our mouth.

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Saliva helps you enjoy the flavours in your food by helping your taste buds break food down into smaller bits. It also helps mash and mix food, so it’s easier to swallow and digest.

Saliva even helps you talk by making it slimy enough for your cheeks, lips and tongue to slip and slide around your mouth to form sounds.

How can you make more good saliva?

Some people don’t make enough saliva because they may be sick or take medicine that stops their salivary glands from working well.

People who make very little saliva have trouble chewing and tasting their food, can get a lot of cuts and sores in their mouth, can be more likely to get holes in their teeth, and have other problems.

To help your salivary glands make a lot of good saliva, you should make sure you drink plenty of water every day (at least one litre). Drink more water after playing sport, especially if you have sweated a lot.

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Arosha Weerakoon has received funding from Colgate for her research. She is a member of the Australian Dental Association as well as the International Association for Dental Research. She is a Fellow of the Royal Australasian College of Dental Surgeons.