Shaping Our Gut Health Through Diet

Written by Clare Carrick ANutr (BHSc)

Scientifically reviewed by Dr Fathalla Ali, PHD Paediatrics


It wasn’t that long ago, in the scheme of things, that we thought of all bacteria as ‘bad’…We now know that this couldn’t be further from the truth. In fact, although the concept can be a little unsettling to some, us humans host trillions of microscopic bacteria, viruses, and fungi… in our guts, mouths, and plenty of other nooks and crannies (1)! And they’re not just here for a free ride! These little critters are absolutely essential to a whole heap of elements of human health…(1) If we look after them, they’ll support us in every way they can, so offering them their favourite foods seems like the least we can do! 


Keeping the Good Guys Alive

Every single person has a gut microbiome that is as unique as their fingerprint (2). Whilst there isn’t one ‘perfect’ gut microbiome to aim for, we do know that more richness and diversity of our gut bugs goes hand-in-hand with good health (2). Our gut bug population is shaped by lots of things we have little control over…how we were born, whether we were breastfed, and whether our parents owned a pet when we were little…but one thing that can have a really profound impact on our gut microbiome, and something that we can change up ourselves, is what we eat (2). 


Let’s take a closer look at how what we eat can change the gut environment. 


Prebiotics: Soul Food for Your Gut Bugs

You can kind of think of prebiotic foods as something we eat to feed our gut bugs, rather than ourselves (2). Prebiotic foods, which come from some plant fibres, are indigestible by humans, and get passed on to feed the gut bugs, which then produce some very useful by-products from this process, known as short-chain-fatty-acids (2). A diet high in these prebiotic-rich plant foods can strengthen the gut wall, reducing ‘leaky gut’, and also help to reduce constipation (2). 


Well-Fed Gut Bugs = Healthier Humans

As mentioned above, when the gut bugs have metabolised the stuff that the humans can’t digest, they produce by-products called short-chain-fatty-acids (SCFAs) (2). SCFAs play a role in some pretty diverse and heavy-hitting aspects of human health, including fat, sugar, and cholesterol metabolism, regulation of the immune system, maintaining tissue barrier function (which helps protect organs), and they can even affect the way our genes are expressed (2)! 


Proteins & The Gut

Not all proteins are created equal in the eyes of our gut bugs. Animal-based proteins, especially from red meat and dairy products, appear to increase the numbers of certain bacterium that are associated with an increased risk of cardiovascular disease and inflammatory bowel disease (2). In contrast, eating more plant proteins has been shown to produce more of those valuable SCFAs, and also increase levels of beneficial bacteria, like Lactobacillus and Bifidobacteria (2).


Good Gut Fats

It might feel counterintuitive to eat fat to feed your gut bugs, but particular fats, especially omega 3 fatty acids, found in seafoods and some nuts and seeds, have been shown to have a positive impact on your gut health (2). As you’ve probably guessed, high intakes of saturated fats from animal products have the opposite affect, potentially leading to imbalances in the gut population, known as dysbiosis (2). 


Not So Sweet Sweeteners

In our highly processed food world, the consumption of artificial sweeteners is on the rise (2). Studies have shown that artificial sweeteners, like saccharin, can change the composition of the gut microbiome, and even lead to some microbe-mediated negative effects, like glucose intolerance (2). According to the research so far, stevia doesn’t seem to have any detrimental effect on the gut microbiome (2).


Fruit and Vegetables For The Win

It may feel like a broken record, but getting your fruits and vegetables in is one of the best ways to  treat your gut bugs right. Getting as much variety as you can will ensure that you are consuming an abundance of vitamins, minerals, antioxidants, and polyphenols from these foods (2). These components have been shown to positively influence the types and amounts of beneficial gut bugs you have, and then, in turn, these beneficial gut bugs can help you to get the most out of the nutrients contained in those foods (2). 


Why Does It Matter?

An imbalance in the gut has been associated with a number of diseases, including cancer, diabetes, cardiovascular disease, obesity, and neurological disorders (2). Our diet is one of the most impactful and modifiable factors we have the power to change to directly and positively impact the composition of our gut microbiome, paving the way for a healthier and happier life (2). 


  1. Rinninella E, Raoul P, Cintoni M, Franceschi F, Miggiano GA, Gasbarrini A, Mele MC. What is the healthy gut microbiota composition? A changing ecosystem across age, environment, diet, and diseases. Microorganisms. 2019 Jan;7(1):14.
  2. Rinninella E, Cintoni M, Raoul P, Lopetuso LR, Scaldaferri F, Pulcini G, Miggiano GA, Gasbarrini A, Mele MC. Food components and dietary habits: keys for a healthy gut microbiota composition. Nutrients. 2019 Oct;11(10):2393. 

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