Gut function and the microbiome – your health depends on it!

Ever heard the saying, “The gut is the seat of health”? A poorly functioning gut has the ability to impact the health of other areas in the body such as immunity, liver function, brain health, weight management and blood sugar regulation.bacteria

Together, the gut and microbiome  form an amazing biological machine.  At the most basic level, they digest food and absorb the nutrients that are freed as a result. But they do so much more! A large part of the nervous and immune system is situated in the gut, which relies on the bacterial population to operate at maximum efficiency. Disruptions to the microbiome result in immune dysfunction, anxiety, depression and sleep disorders.

Nervous System

The enteric nervous system (situated in the gut) is part of the autonomic nervous system, receiving information from both sympathetic (fight or flight) & parasympathetic (rest & digest) divisions. It regulates the function of the digestive organs, and is enormous. Operating mainly on its own with very little input from the central nervous system, it acts as an integration centre, transmitting information back to the brain.  About 90% of the fibres in the vagal nerve carry information to the brain, not vice versa (1). For this reason, the gut has earned the title of the “second brain”.

Because of their interaction with the nervous system, gut flora have a significant impact on human behaviour and cognitive processes. There is a large body of research which now points to brain & immune development of children being partially dependent on the make-up of their microbiome. A newborn’s gut flora is largely determined during birth and early childhood. Researchers theorise that this provides evidence as to why more Caesarean-born children suffer from allergies, as opposed to those who experience vaginal birth –  they are not exposed to the mother’s natural flora.(5)

Gut bacteria assist in the production of neurotransmitters like serotonin and GABA. In fact, somewhere between 80-90% of serotonin produced in the body is made in the gut. (3) In terms of those suffering from depression, anxiety and other mood disorders, the ramifications of a poorly functioning gut are substantial. Co-morbidity for depression and IBS, Crohn’s disease or ulcerative colitis are common, therefore the link between gut and brain health cannot be dismissed.


A large part of the immune system is situated in the gut. Gut associated lymphoid tissue (or GALT) is a large collection of  lymph nodes & tissues that provide immune defence. Lymphocytes  patrol above and below the gut lining to protect against infectious pathogens which may otherwise enter the bloodstream. Good gut bacteria can communicate with the intestinal lining directly, and this leads to activation/suppression of the underlying GALT tissue as required. (1)Problems with immunity can arise when there is an imbalance of bad bacteria in the gut as an overgrowth of pathogenic bacteria causes fermentation, inflammation and ‘leaky’ gut.

Modifying the Microbiome

Clinical studies have proven that pre and probiotic treatment can assist sufferers of gut conditions and mood disorders alike. Microbiome modification is showing huge promise in areas such as treatment-resistant depression, autism, even schizophrenia (4). However, for long-term management of a sustainable microbiome, diet must be addressed. A diet high in processed foods, saturated fats & sugar is more likely to promote imbalances and dysbiosis. A diet high in vegetables, fruit, good quality protein and essential fatty acids promotes a healthy, self-sustaining microbial population.

Supplements such as Slippery Elm, Turmeric, Licorice, glutamine and Saccharomyces boulardii (and other probiotics) can help support gut function by providing food for gut bacteria, reducing inflammation and protecting the lining of the digestive system.

Please talk to us today if you would like to know more about protecting your gut health!


Nepean Naturopathic Centre – making health easy



  • Forchielli, M.L & Walker, W.A (2005). The Role of Gut Associated Lymphoid Tissue and Mucosal Defence. British Journal of Nutrition. 93,(1), S41–S48
  • Verna EC, Lucak S. Use of probiotics in gastrointestinal disorders: what to recommend? Therapeutic Advances in Gastroenterology. 2010;3(5):307-319.
  • Murphy, E.A., Velazquez, K.T., & Herbert, K.M. (2015). Influence of a high-fat diet on gut mirobiota: a driving force for chronic disease risk. Current Opinions in Clinical Nutrition and Metabolic Care. Sep;18(5):515-20
  • TANAKA, Y., TAKAMI, K., NISHIJIMA, T., AOKI, R., MAWATARI, T., & IKEDA, T. (2015). Short- and long-term dynamics in the intestinal microbiota following ingestion of Bifidobacterium animalislactis GCL2505.Bioscience of Microbiota, Food and Health, 34(4), 77–85.
  • Williams, D. (2015).Probiotic Species and Strains: What Are Their Differences?Retrieved from