5 Weird and Wonderful Things About the Gut

5 Weird and Wonderful Things About the Gut

Did you know that we’re more bacteria than human? These weird and wonderful facts from our gastroenterology dietitian Dr Sammie Gill will blow your mind. And should be saved for the next pub quiz.

You’re more microbial than human

The human microbiome is the collection of all the microbes that live in and on us (around 40 trillion in total). The majority of these microbes live in the gut (more specifically, the large intestine) and are collectively known as the gut microbiome.

In fact, we are more microbial than human, at a ratio of 1.3 bacteria cells for every one human cell…

…although it’s likely to be more than this since this estimate doesn’t account for other communities that live in the gut such as viruses (coined the ‘gut virome’).

Your microbes have distinct roles and responsibilities

Although we’re still learning exactly which specific microbes do what, we know that they have distinct roles and responsibilities.

For example, the species Ruminococcus bromii has the superior ability to break down some forms of resistant starch (a type of fibre). On the other hand, Ruminococcus champanellensis champions at degrading cellulose (another type of fibre).

Each part of your gut has a specific purpose

There is a lot of pipe work inside you – around 8-9 meters in fact! And it runs all the way from one end to the other. Each part of your gut has a specific purpose and serves a different function.  Here is a quick summary…


Your stomach can produce up to 4 litres of acid every day! The main purpose is to kill off any bacteria that could be harmful and prevent them from entering the body. 

Your stomach also acts like a washing machine, churning up the food you’ve just eaten into a nice baby-food like mixture which is then drip fed into the small intestine.

Small intestine

The small intestine is not so small. In fact, it’s larger than the large intestine. Thanks to the finger-like projections, it has an impressive surface area to maximise absorption of nutrients.

What’s more, different nutrients are absorbed at different points along the small intestine. For example, most calcium and iron are absorbed in the first part, whereas carbohydrates, fats and proteins are absorbed later on.

Large intestine

The large intestine is where the magic happens! It’s the place our trillions of microbes call home. This community is a hub of activity, playing a crucial role in our overall health.

The large intestine is also responsible for absorbing remaining water and solidifying waste to create a fully formed poo.

Your gut microbiome changes over time

Your gut microbiome is never static. It’s mouldable and changes depending on what you expose it to. For example, studies have shown that the type of microbes present in the gut can change within as little as 24-48 hours if you suddenly switch your diet to a plant-based one.

Your gut microbiome also evolves during your life. In the first few early years, the gut microbiome is vulnerable, becoming more stable and diverse to reach an adult-like state by the age of 2-4 years old. Likewise, as we get older, there is a progressive loss of diversity (and why there is now so much research focus on targeting the gut microbiome in ageing).

There are more questions than answers

The gut is wonderfully complex and mysterious organ, but there are more questions than answers and what we don’t know is more than what we do know.

But, what we do know is that the gut has huge potential, specifically the gut microbiome as a therapeutic target to support physical and mental health.

Find out 5 reasons you're gut is more important than you think.