Appliance of Science: Why do we burp?

Everybody burps, and in some cultures it is even considered polite to do so after a meal; it is seen as a sign that you have enjoyed your food. But why do we burp? Dr Naomi Lavelle has the answer.

Everybody burps, and in some cultures it is even considered polite to do so after a meal; it is seen as a sign that you have enjoyed your food.But why do we burp, do other animals do it and what would happen if we didn’t? Dr Naomi Lavelle explains.

What exactly is a burp?

First up, what exactly is a burp?

The medical name for a burping is eructation.

It is simply the release of gases from the body, through the mouth.

It is actually a very important bodily function as it allows gases that have built up in the stomach, out of the body.

How does the gas get into our stomachs in the first place?

You might be surprised how many ways we can introduce gases to the stomach.

Firstly, when we eat and drink we usually take in more than just the food and liquids; we take in small amounts of air too.

We can reduce the amount of air we take in by eating slowly and chewing our food well. The foods we eat can add gases to our stomachs too. Some more than others.

Certain foods, like beans and pulses can release gases as they begin to be digested in our stomachs. High fibre foods, some vegetables and processed foods can also release gases in the stomach.

Fizzy drinks are full of a gas called carbon dioxide and this gets released into the stomach once we drink them.

Our bodies have a good way to release these gases, they simply send them back up the way they came and they pass out our mouths as burps.

What makes the burp sound?

When we burb, the gases come back up the way they came, through the oesophagus (our food pipe).

The burping sound is most likely made by the flapping of soft tissue at the top of the oesophagus as the gases pass by and out the mouth. This tissue is located at the top of our throat.

Is a fart just like a burp that comes out the other end?

I have been asked this question a lot too but no, farts and burbs are two different things.

They are usually made up of different gases.

Burps mainly contain gases from the stomach, like oxygen, carbon dioxide and nitrogen; farts can contain these gases too but usually also contain other gases such as methane and sulphur, produced when bacteria in our intestine break down undigested food.

Do all animals burp?

Most mammals burp just like us. Fish burp too.

There are some animals though that we know don’t burp, like rats.

Although there are no official recording of birds burping, it is likely they do burp too.

What would happen if we didn’t burp?

The gases that build up in our stomach have to escape somehow, so if they doesn’t come out as a burp, they will most likely continue on down our digestive tract, leaving our body from the other end, as a fart.

If the gases get trapped inside our body for a while our stomach will start to swell a little and this can make us feel bloated and quite uncomfortable.

In theory, if the gases really couldn’t escape our body they would keep building up until our stomach eventually exploded.

Luckily our bodies are well equipped to make sure this doesn’t happen.

So instead of seeing a burp as something a little impolite, remember what good it is doing.