You may have heard about the gut microbiome, it is a topic that is certainly getting more attention in recent years, but just what is the gut microbiome and what role does it play on our overall health? We chat to Dr Sammie Gill, specialist Gastroenterology Dietician from Symprove to take a look under the microscope on this very important subject
What do we need to know about the microbiome and its influence on our gut and overall health?
Your gut is a powerful organ – it has the potential to influence the health of every organ in the body. Look after your gut.
Thanks to the explosion of research in the last few decades, we are becoming more and more aware of the importance of the gut in shaping our overall health.
This has mainly been driven by a surge of interest in the trillions of microbes that live in the gut (collectively known as the gut microbiome). This complex ecosystem produces important compounds (such as short-chain fatty acids, hormones, vitamins and chemical messengers such as serotonin and dopamine) that have been linked to many aspects of physical and mental health.
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 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 gut microbes are mentors to your immune system
70% of your immune system sits along your gut. Impressive, right? But our gut microbes have a huge role to play in how it behaves. In fact, they support the immune system to develop by teaching and training it to react appropriately – to trigger a response to potentially harmful microbes and to remain tolerant to harmless ones.
Your gut microbes do things you can’t
Your gut microbes are more than just allies; they perform functions the human body can’t. For example, they break down all of those non-digestible nutrients (such as fibre and plant chemicals) and in exchange, release beneficial molecules such as short-chain fatty acids (SCFAs) which play a key role in gut health, such as supporting the gut barrier.
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
Gut health doesn’t just refer to the gut microbiome. It refers to the inner workings of the entire gastrointestinal tract – the long hollow tube which spans from one end to the other with different ‘food processing stations’ along the way, including the stomach, small intestine and large intestine.
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…
Stomach
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!
What influences a change in our gut microbiome?
While your gut microbiome is unique to you (a bit like your fingerprint), your gut microbiome is never static. It’s mouldable and changes depending on what you expose it to.
For example, what you eat – 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 from a meat-based diet to a plant-based one.
Many things play a role in gut health including whether you have a pet, how much time you spend outdoors, how much physical activity you do, how much sleep you get, what medications you take, and how stressed you are, and where you live (to name a few!).
How might we feel if our gut microbiome is off kilter?
While there is no one measure of ‘gut health’, some classic signs that your gut may need some attention is if you’re experiencing symptoms such as pain, bloating, or gas.
Your poop habits can tell you a lot about the inner workings of your gut. Ideally, poo should be soft, bulky and easy to pass. Typically a shade of brown – transient changes can occur – certain foods (such as beetroot) and medications (iron supplements) can do this.
There is a huge range when it comes to frequency. Anything from three times per day to three times per week is considered ‘normal’. But ultimately, it’s what is normal for you.
But there may be other signs. Think about how you’re feeling – are you feeling tired all the time? Are you susceptible to colds?
Be mindful of your microbes and look after them.
The mind body connection is being linked to our gut more than ever, how does the microbiome influence our mental health?
For a long time, the gut and the brain were thought of as separate entities – the gut was responsible for digestion and the brain was responsible for emotions.
Fast forward to the present day, we know this isn’t the case at all.
The gut and the brain have a very intimate relationship and are in constant communication with one another – called the ‘gut-brain axis’.
An unhappy gut will send signals to the brain letting it know, and an unhappy brain will send signals to the gut letting it know. It’s a two-way street. For example, gut symptoms can be the result of our emotions (low mood, anxiety, stress) or the cause of our emotions (low mood, anxiety, stress).
But how exactly do they communicate? It’s complex, but they talk using four key channels, including the gut microbiome, the nervous system, the hormonal system, and the immune system
How can we change our microbiome for the better?
It’s important to focus on the things your gut microbiome needs. For example, lots of plant-based diet diversity (including wholegrains, nuts, seeds, herbs, spices, veggies, fruits, legumes), getting good quality and quantity of sleep, and minimising stress.
Focus on adding in, rather than taking away. Work from the inside out– our gut health is central to our overall health so target the gut microbiome with a nutrient-dense plant-based diet. Variety is key – a hallmark feature of a healthy gut microbiome is diversity.
Plant-based foods are packed with different types of dietary fibre – a nutrient our gut microbes love, as well as vitamins, minerals and plant chemicals including polyphenols.
Remember, it’s not just about what you eat, it’s also how we eat. Try and ringfence time for eating, if you can. Minimise distractions (e.g. phone, TV) and chew your food well to help with digestion.
Why is supplementing with live bacteria better?
Ingesting bacteria that are live at the point of consumption allows the opportunity to exert health effects as soon as they reach the gut.
Thank you to Sammie Gill and Amy Allcock from Symprove for their help in creating this post and for their insight into the gut and the huge role it plays in our overall health and wellbeing.
