Trillions of bacteria and other microbes live inside your gut, collectively known as your “gut microbiome.” Far from being harmful, these microorganisms are vital to your health, supporting everything from your immune system and heart to brain function and mood.

Your diet determines your gut microbiota. It can either support it, by feeding the healthy bacteria, or disrupt it, damaging your intestinal microbes and causing broader problems.

Below, we’re covering the gut microbiome: what it is, why it’s important, and how it affects your health. We’ll also look at what you can do to support your gut microbiome clinic.

What Is the Gut Microbiome?

Your gut microbiome is all the non-human cells living in your gut. There are trillions of bacteria and other microbes living within your gut, helping you digest fibre and releasing compounds that influence how your body functions — even your mood.

Most of these microbes are found in a pocket of your large intestine known as the caecum — it’s the dividing point between the large and small intestine (where your appendix is).

Different people have slightly different gut microbiota. But there can be thousands of different species. In one study called the PREDICT program, identical twins had around 34% of their gut microbes in common; usually, it’s around 30% in unrelated people.

So, it’s extremely unique to each person.

Why Is the Gut Microbiome Important?

Most of us are raised to think of bacteria as being bad. But that’s not the case. In fact, we evolved alongside bacteria, forming symbiotic relationships that support our health.

The “good” bacteria in our gut:

• helps digest food by breaking down complex carbohydrates, fibres, and proteins that the body can’t process alone.

• produces vital nutrients, including vitamins B12 and K, as well as short-chain fatty acids (SCFAs) like butyrate that nourish the gut lining.

• regulates the immune system, training it to respond appropriately and preventing excessive inflammation.

• protects against pathogens by competing with harmful bacteria and strengthening the gut barrier.

• influences metabolism by affecting how the body stores fat, regulates blood sugar, and balances energy.

• supports brain function through the gut–brain axis, influencing mood, stress levels, and cognition.

Your gut microbiome isn’t only beneficial microorganisms. It’s a delicate balance of over 100 different species (out of over 1,000 possible species). The most dominant organisms are:

• Firmicutes, including Lactobacillus

• Bacteroidetes, including Prevotella

• Actinobacteria, including Bifidobacterium

These bacteria initially come from your mother’s birth canal — exposure happens at birth. Then, as you grow, the colony begins to diversify. It’s believed that a higher microbiome diversity is good for your health.

The Effect of the Gut Microbiome on Your Health

So, a diverse gut microbiome is good for you. It supports many aspects of your body, from digestion and nutrient availability to immune regulation and metabolism.

But what happens if your microbiome isn’t quite right?

Well, the evidence indicates that “dysbiosis” — an imbalance in your gut bacteria — can lead to obesity, heart disease, diabetes, and even cancer.

In the gut itself, dysbiosis is linked to conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). So, if you notice symptoms such as bloating, cramps, or abdominal pain, the underlying cause might be your gut microbiome.

Indeed, people who take probiotics (containing Bifidobacterium and Lactobacilli) can relieve IBS symptoms. Because your gut bacteria rely on what you eat, your diet is the single biggest factor shaping your microbiome.

Your Diet and the Gut Microbiota

Most animals have a preferred diet. The presence of certain foods in an environment can determine if an animal thrives or dies. The same is true for bacteria.

Feeding your gut microbiota a variety of different and nutritious foods helps them to thrive and survive. Opting for large amounts of ultra-processed foods may not be as supportive.

To support your gut microbiome, you can:

• Eat fermented foods like kimchi, sauerkraut, or yoghurt – they contain friendly live bacteria

• Add a wide variety of healthy foods to your diet (particularly different colours)

• Reduce your intake of ultra-processed foods

• Give yourself a gap between meals to let digestion happen

• Up your intake of plant-based foods

You might also want to consider taking a specific probiotic supplement. They contain healthy bacteria, crucial for replacing any lost good bacteria. You may notice some disruption after taking antibiotics, so it’s a useful remedy to get your gut microbiota back on track.

Get Your Gut Microbiome Checked

Suspect your gut microbiome may not have the right balance? The Function Gut Clinic offers the UK’s first fully integrated, full-spectrum microbiome clinic.

We offer a range of tests:

• Stool microbiome analysis

• Hydrogen sulphide breath testing

• SIBO breath testing (hydrogen and methane)

• Gastric acid output testing

• Gut motility and transit studies

• Gut permeability assessments

Together, these tests inspect your gut microbiome, identifying any issues and providing a roadmap to better digestive health. You’ll receive a full action plan and ongoing care and support.

Book your microbiome test today and take control of your digestive health.