By: Robyn Chuter, Naturopath 

The Universe Within Us – Part 1:

For a century, researchers have slowly but steadily gathered knowledge of the bacteria that inhabit the human gut, their progress hindered by having to rely on culturing bacteria recovered from stool in a petri dish.

Gut microbiota research as we now know it only really got underway in the late 1990s, with the development of technology that allowed scientists to sequence the DNA of our gut bacteria.

At this point, it was discovered that the vast majority of the teeming hordes of tiny critters that inhabit our insides can’t be cultured at all, as they die when exposed to air.

And no one would have believed in the last years of the twentieth century, just how great an influence these microscopic life forms would be discovered to exert on every aspect of human health and wellbeing.

The field of gut microbiota research has mushroomed so dramatically, that a scientific paper published in 2018 calculated that over four-fifths of the total number of scientific publications focusing on the gut microbiota over the previous 40 years were published in just four years, 2013  ̶  2017.

And now in 2021, so many scientific articles on the topic are published every day that it’s impossible to keep up with them all.

In just a few decades, researchers have come to understand that the communities of bacteria, archaea, protists, fungi and viruses that live inside our gastrointestinal tract (our gut microbiota), and their collective genetic material (our gut microbiome) are so vital to healthy function that they constitute a distinct organ of the human body.

Here are just some of the roles played by the 100 trillion microorganisms that populate our gut:

Immune functions: Formation of the gut-associated lymphoid tissue, or GALT (a key component of the immune system in the gut) and ‘training’ of our immune cells to distinguish self from non-self, and friend from foe.

Gut functions: Maintaining the intestinal barrier (that is, preventing and repairing leaky gut); digesting complex carbohydrates found in human breast milk and plants; producing short-chain fatty acids which feed the cells that line our colon; keeping disease-causing bacteria, yeasts and fungi at bay; regulating muscle movement in the intestinal tract (motility); and protecting against colon cancer.

Metabolic functions: Regulating serum cholesterol, blood glucose levels and appetite.

Vitamin production: Producing vitamins B1, B2, B12 and K, along with biotin, folate B9 and alpha-lipoic acid.

Central nervous system functions: Stimulating development of parts of the brain, especially the hippocampus (which plays key roles in motivation, emotion, learning and memory); and producing chemicals that affect areas of the brain involved in appetite control and food cravings.

Enteric nervous system (‘gut brain’) functions: Producing neurotransmitters – chemicals that nerve cells use to talk to each other, and to muscles and glands – including GABA, serotonin and dopamine  ̶  and influencing the neuroendocrine cells in the gut that also release these neurotransmitters.


Is your gut telling you it’s time for a healthy change? Need help to get your health back on track? Apply for a Roadmap to Optimal Health Consultation today.


Robyn Chuter is a Naturopath, Counsellor and ASLM Certified Lifestyle Medicine Practitioner,

 [email protected]

 Keen to learn more? A recording of Robyn’s presentation Two brains, 100 trillion bugs is available here