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A simple guide to understanding what gut health actually means. Read on to discover the microbiome’s role in gut health. How immunity is shaped by our bacteria. And how to test for and maintain this elusive thing called gut health.


Gut health is a 272 million page topic. And growing.

According to Google – there are millions of people talking about the health of the human digestive tract.

Hundreds of millions!

That’s kind of a lot.

  • Which tells us we are onto something.
  • And something big.
  • Something important.

But with so many different perspectives it’s a noisy space.

Once you start digging it’s really easy to get lost in all the cleanses, protocols, books, courses, diets, programs and just all of it.

And avoiding overwhelm is key.

There is just so much information!

Want to know how to weed out the fads?

With facts.

Gut health 101.

Understanding how it all works, so you can formulate your own educated opinions.

So let’s get started.

And I promise to make it simple!

What Is Gut Health - Mamabiome

What Does Gut Health Actually Mean?

First, let’s talk definitions.

Is there a universal, medically accepted explanation for gut health?


Not yet.

Gut health is still being discovered.

  • Scientifically speaking, it’s a hot topic.
  • New research papers are published daily.
  • So the line in the sand (the molecular detail) keeps shifting.

But we have a pretty good idea.

Obviously it starts with what we put in our mouths and ends with what emerges from our derrière.

Just in case you need a lovely visual…

Digestive Tract - What Is Gut Health - Mamabiome

But you want science, yes?

What we think we know about gut health is this…keeping in mind science changes – it’s a fickle friend

The optimal state of a healthy gut encompasses 5 key criteria.

A healthy gut:

  1. Effectively digests and absorbs food. Giving a normal nutritional status. Effective absorption of food, water and minerals. Regular bowel movements. Without pain, bloating, constipation, vomiting or diarrhoea.
  2. Is free from illness. From the stomach to the colon. Without stomach ulcers, reflux or inflammatory disease. No IBS, coeliac or other inflammatory conditions. No cancer.
  3. Has a normal and stable intestinal microbiome. Without bacterial overgrowth. Normal composition. Free from infection.
  4. Supports an effective immune status. Meaning the gut acts as an effective barrier to pathogens. With the lining working to protect against foreign invaders. And normal levels of mucus, antibodies, immune cells and no hypersensitivity or allergic reactions.
  5. Promotes a status of wellbeing. A normal quality of life. A positive ‘gut feeling’. With balanced happy hormone serotonin production and normal nervous system function.

Which really puts it in perspective.

Gut health not only implies a healthy digestive tract and microbiome, but also effective immunity and positive mental/emotional health.


The next step is to understand WHY the gut effects everything.

Why Is Gut Health So Important?

The key lies with understanding how much the gut actually does.

Beyond mechanical processing of food. Beyond nutrient and fluid uptake.

The gut also has a hand in:

  1. Communication. Bacteria have chats with our cells via enzymes. So your gut bacteria are basically in direct communication with the rest of your body.
  2. Regulation. Major immune functions are controlled by the gut. Think allergies, skin conditions autoimmune diseases.
  3. Cooperation. The gut reports to the brain to influence hormones, energy and so much more. The gut and the brain are in cahoots!

Essentially the effects of the gut are so widespread, that gut health is the new ‘health’.

And in our body, it comes down to two things.

  1. The health of our gut barrier (our digestive tract cells).
  2. And our gut microbes.

Let’s take a look at them both in more detail.

What Is The Gut Microbiome?

You’ve probably heard that we are more microbe than human.

That there are an estimated 10x more bacterial cells living in and on your body than your very own human cells.

It’s staggering to imagine.

But remember how fickle science can be? This ‘data’ keeps changing.

One estimate, puts our bacterial total at around 1014.

Which in words is … one hundred trillion.

To get some perspective…

  • 106 is one million
  • 107 is ten million
  • 108 is one hundred million
  • 109 is one billion
  • 1012 is one trillion
  • 1014 is one hundred trillion … 100,000,000,000,000 microbes.

So literally a crap tonne.

Another science-y guess is based on number of bacteria per millilitre of fluid along the digestive tract. This estimate is even more mind boggling.

Gut Microbiome Graph - What Is Gut Health - Mamabiome

By the time our digested food reaches the colon, it may contain up to one trillion microorganisms per mL!

Say what!

But crazy educated guessing aside, the message is … your gut microbiome bacteria mainly hang out in your large intestine.

And the combination of  bacterial species that live there are unique to you. 

They are dynamic – always changing.

It depends on what you ate yesterday, where you live, your lifestyle choices, stress and just everything.

If you are interested in what kind of bacteria are living in your gut, this will be covered in an upcoming post. You can [thrive_2step id=’377′]subscribe here[/thrive_2step] to receive notifications when new posts are published.

How is our microbiome damaged?

  • Antibiotics.
  • Carbohydrate-rich diets.
  • Chemicals and pesticides.
  • Heavy metal toxicity.
  • Stress.
  • Modern life.

And just as our microbes are crucial for gut wall health, the health of the gut wall also affects the microbes.

It’s a symbiotic relationship. One where both sides benefit by the presence of the other.

So to maintain gut health we need …

  1. A normal microbiome, with many different and diverse species PLUS
  2. An intact gut wall that cooperates and counteracts the bacteria

How Do The Gut Barrier And Microbiome Interact?

Now, let’s explore the barrier between you and your food.

It’s more technical name is the gastro-intestinal barrier. Or GI barrier.


  • gastric = stomach
  • intestinal = intestines
  • barrier = barrier …

The GI barrier both CONTROLS and DEPENDS ON the gut microbiome.

Want a closer look at how?

Gut Barrier + Microbiome Interactions - What Is Gut Health - Mamabiome

  • Supporting digestion. Digestion of fibre and other nutrients are entrusted to our microbes.
  • Regulating gut wall functions. Like mucus production, making antimicrobial compounds and holding the junctions that keep intestinal cells tightly together – i.e. not leaky.
  • Gate keeping. They prevent colonisation by potentially pathogenic (“bad”) bacteria.
  • Providing energy. Undigested food like fibre is used by bacteria to provide energy to the gut wall. Note to self – eat more resistant starch!
  • Regulating immunity. Educating the infant immune system by their bacterial presence. And also throughout life by challenging immunity via specialised immune cells in the gut wall. They keep us on our toes!

But their MOST IMPORTANT job is to keep the gut barrier intact.

Bacteria act tiny as gardeners in our gut.

  • Maintaining the integrity, diversity and health of our intestines!
  • We need them just as much as they need us. Maybe more.

Loss of our gut wall integrity (and bacterial population) is linked to infectious disease as well as inflammatory and allergic diseases.

Like IBS and eczema.

And ultimately a decreased immune system and loss of effective gut function.

The Gut And Immunity

We know that a major function of the gut wall is immunity, right?

It’s why soup is often prescribed for a cold – by knowing old ladies and modern gut-conscious mamas.

And also why we tend to get sick after festive holidays.

  • Like Easter and it’s ridiculous chocolate gorging.
  • Or Christmas and it’s eat-all-the-things binge.

You know the feeling…bloated, tired, lethargic.

  • When your top jeans button is bursting, eagerly waiting for you to leave nana’s Christmas lunch.
  • So it can unbutton and recover a little…before heading out for yet another Christmas dinner.

Your poor gut bugs just can’t keep up!

And consequently, your immune defences go down.

Gluttony aside, the science behind gut immunity is super interesting!


How Gut Bacteria Affect Immunity

Gut Health Fact - What Is Gut Health - Mamabiome

The very presence of your gut bacteria constantly challenges your immune system.

And this is a VERY good thing.

Are you ready for a super basic immunology lesson?


  • So, bacteria are covered in tiny antenna looking things, called antigens. They act like specialised keys.
  • These antigens alert specialised immune cells to the their presence. By sticking to the cells’ little receptors – which act like a lock – just for the antigens! Key + lock = ALERT!
  • These cells, called T-cells, B-cells and phagocytes then start the “immune fighting”process of eliminating the microorganism.
  • And it’s this communication between bacterial antigens and immune cells that develops our immune system. And of course the immune cell cascade and molecular learning that follows.

But essentially, all the bacteria floating about in your gut are constantly triggering immune cells.

Teaching your immune cells what’s what.

And determining who is friendly and who isn’t.

Crazy huh!

It’s obviously far more complex than this explanation, but you get the general gist.

More Gut Immune Functions

And the gut has even MORE tools that contribute to immunity.

Wanna see?

  • IgA. Immunoglobulin A, the first line of defence antibodies against invading bacteria, viruses and toxins. These guys are made by special cells in the mucus membranes of the digestive and respiratory tracts. And your gut bacteria actually stimulate their production.
  • Making mucus. Goblet cells in the gut produce mucus to protect the microorganisms living on the gut wall. And to protect the gut wall itself from invaders. Your gut microbes regulate this too.
  • Antimicrobial compounds. Specialised Paneth cells make antibacterial proteins called defensins which add another layer to the immune defences of the gut.

These guys are part of a complex interaction between the specialised cells in the gut wall and the microbes that live there.

Learning, communicating and protecting you.

Makes more sense now, yes?

The Gut And The Brain

Get ready for another impossible to remember term…and acronym.

The. Enteric. Nervous. System.


I know, so many eye-glazing science names. And just for fun, the Enteric Nervous System is also known as the Intrinsic Nervous System.

Why do they do this to us!?!

But seriously…

It’s just a science name for your gut-brain.

The massive network of nerves that exists in your gut. That talk to your brain.

And we are only just beginning to understand it.

Gut Brain - What Is Gut Health - Mamabiome

What we know…

  • It’s huge. The comprises the largest network of nerves outside the brain. With one hundred million neurons!
  • It watches. Conditions inside the gut are monitored via receptors and nerve cells which are activated by compounds like serotonin and histamine.
  • It regulates. Secretions, absorption, immune functions, permeability (what gets through the gut wall) and even the microbiome.

And emerging science is showing the link between the gut-brain-axis and chronic gut disease. Like irritable bowel disease. And mental illness, like depression.

It’s all connected with the ENS.

The exact mechanisms are still “as yet undefined”.  Meaning they don’t fully understand it just yet.

But many studies show that changing your gut microbiome affects both the gut AND the nervous system.

At the same time.

What Gut Changes Affect The Brain?

Super simple, straightforward, everyday stuff.

  • Taking probiotics – helpful bacteria found to benefit digestion, immunity, inflammation and general health.
  • Adding prebiotics – indigestible plant fibres are the food probiotic bacteria feed on.
  • Reducing carbs – making dietary choices that feed our resident probiotics by limiting food for ‘bad’ bacteria, yeasts and parasites.
  • Antibiotics – in severe cases antibiotics are used by integrative doctors to wipe out flourishing trouble makers and then rebuild a more favourable microbiome.

So as the saying goes you are what you eat.

Because your body counts on you to feed your microbes not just your tastebuds.

How Is Gut Health Tested?

Now comes the tricky part.

How the heck do we know if we ‘have’ gut health?

Is there a test?

Yes, there are many.

  • Surveys. Lengthy questionnaires like the Inflammatory Bowel Disease Questionnaire for IBS suffers. Which measures quality of life based on gut health. And highlight symptoms of poor gut health.
  • Scoring Systems. There are many specific scoring and profile-based assessments. Like the Bristol Stool Scale and numerous others.
  • Eating Habits. Week long food history and frequency assessed by specialised software. And of course by educated eyeballs.
  • Biological markers. These are lab tests that integrative and functional medicine practitioners use to assess function and biochemical changes specific to a body system. Pathology tests.
  • Faecal microbial analysis. Detailed testing about who is living in your poop. Based on who is found and how many of them, you can get a good idea of the state of the microbiome.

Really, though the ultimate test is how you feel.

Your inbuilt wellness indicator.

Kind of like how you don’t need a test to alert you to the fact you’ve caught a cold.

You feel unwell.

And have symptoms typical of someone was has a cold-virus rampaging around.

Heal Thy Self - What Is Gut Health - Mamabiome

  • You just know.
  • Your body knows.
  • And your body also knows how to heal – we just have to give it the right environment.

I’m not saying tests are not helpful, they absolutely are.

However, you need the right person to request the right test and then to accurately interpret it.

And sadly, wonderful holistic practitioners are tricky to find.

But they are out there!

Finding help

A great place to start looking, is the Mindd Foundation.

  • They have a searchable database of functional medicine doctors and practitioners here in Australia.
  • A whole lot of amazing information.
  • And connections with international Functional Medicine providers as well.

But ultimately YOU need to know how to maintain a healthy gut.

Because YOU feed your body.

Not your doctor, not your naturopath nor your knowledgable friend Ashleigh.

Its all on you.

So find help. But be prepared to make changes. And stick to them!

How To Maintain Gut Health?

The options are many and varied. And highly dependent upon individual conditions and circumstances.

But here are some general guidelines.

Find balance.

This is based on the hygiene hypothesis.

  • Which explains the need for balance between the microbiome and gut immune system.
  • Otherwise the GI barrier integrity is impaired.
  • Which leads to poor gut health and GI disease.

There is evidence that parasitic helminths [worms] and commensal microbial organisms [good bugs] co-evolved with the human immune system and that these organisms are vital in promoting normal immune development.1

So we want to it intact and functioning optimally.


With balance AND avoiding conditions that disturb this balance.

Finding Your Balance - What Is Gut Health - Mamabiome

Finding a happy medium.

  • Enough activity. Somewhere between lack of exercise and extreme exercise.
  • Sufficient stimulation. A place between extreme stress and absolute boredom.
  • Diet balance. One that mostly consists of plants. High in vegetables and fibre. Low in processed foods. But sometimes to start, an elimination protocol might work best to promote healing.

Avoiding or limiting disruptive triggers.

  • Tobacco smoke.
  • Alcohol.
  • NSAIDs. Non steroidal anti-inflammatory drugs. Like ibruprofen, paracetamol etc.

Promoting a state of calm.

  • Meditation.
  • Breath-work.
  • Yoga.

Another well researched option is taking a probiotic or including more prebiotic foods in your diet.

There’s no single “right” way.

Feel it out.

1 Stiemsma, Leah T et al. “The Hygiene Hypothesis: Current Perspectives and Future Therapies.” Immunotargets and Therapy 4 (2015): 143–157. PMC. Web. 21 Oct. 2017.

What To Do Now…

Let your body guide you.

This is one of the biggest and best-est things I’ve rediscovered during my gut health journey.

  • Re-learning to trust what my body tells me.
  • Tuning in. Feeding it what it wants. Not feeding it what makes it unwell.
  • And connecting science with my body’s innate wisdom.

So by now I hope you too have gained a better science-y understanding of what gut health is and why it’s important.

And are feeling a little more confident and prepared to tackle the crazy information explosion.

Just remember, it’s with understanding why, that we can create lasting change.

What Is Gut Health? – Nutshell Version

Here’s what we’ve covered.

  1. A gut health definition. There isn’t one. There are many. Covering all aspects of health and wellbeing and the 5 key criteria for gut health: nutrition, lack of disease, a normal microbiome, effective immunity and ultimately feeling well.
  2. Why gut health is important. Because the gut does far more than mechanically process food and absorb nutrients. It communicates, regulates and cooperates with microbes, immune cells and the brain.
  3. We explored the gut microbiome. A massive contributor to our cellular ecology. With an estimated 1014 organisms – mostly living in our large intestine.
  4. Investigated the gut barrier. The symbiotic relationship between us and bacteria. How the intestinal barrier mediates a strong relationship between our gut microbes and immune pathways.
  5. Talked about how the gut tackles immunity. The interaction between our immune cells and the role microbial antigens play in challenging our immunity.
  6. The gut-brain connection. We learned about the ENS and the massive number of nerve cells entangled in our gut.
  7. How gut health is tested. The many tools we have to measure gut health and the necessity for integrative medical practitioners.
  8. Ways to maintain gut health. A general approach to maintaining balance between our microbes and the cells we require for health. Avoiding harmful conditions and embracing those that promote wellbeing.

There you have it!

Gut health 101.


With simple daily diet and lifestyle changes you CAN create a state of gut health in your life.

We did.


Victoria x

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