Are the ‘bugs’ living inside us the key to our health?


For the summary & take-home message CLICK HERE

In recent years, the world of health and wellness has been abuzz with terms like ‘probiotics’, ‘microbiome’, and ‘gut-brain connection’. Everywhere we turn, from trendy nutrition blogs to advertisements for the latest fermented foods, there’s a growing fascination with gut health. But what’s behind the hype, and why has gut health become a hot topic in the world of science and well-being? That’s what we are going to cover in this article. 

What is the gut microbiota and how does it influence our health? 

The gut microbiota is the collective term for the array of microorganisms, including bacteria, viruses, archaea and protozoans, that inhabit the gastrointestinal (GI) tract of a particular person. Recent studies have found connections between the gut microbiome and a wide array of health conditions, including obesity, autoimmune diseases, and mental health disorders. Understanding the composition and function of gut microbiota has the potential to revolutionize healthcare by enabling personalised treatments. The gut microbiota is made up of up to 100 trillion symbiotic microbes (mutually beneficial relationship between the human and the microbe)!1 The gut microbiota feeds on food residues that the human body does not digest, mucus secreted by the gut, and dead cells that are shed, which keeps their population levels high.2 

The microorganisms living in your gut produce a large number of physiologically active substances, including short-chain fatty acids, vitamins, anti-inflammatory, analgesic (pain-relieving), and antioxidant products, along with neurotoxins, carcinogens (cancer-causing substances), and immunotoxins. These products can enter the bloodstream, directly regulate the expression of genes, and affect the body’s immune and metabolic processes, including energy balance. 

The intestinal barrier comprises a layer of epithelial cells that are tightly connected by structures, called tight junctions, and mucus. It blocks the entry of diverse exterior antigens including food antigens, bacteria, pathogens, and toxins while simultaneously absorbing nutrients and acting as a lubricant.2,3 This barrier also provides important components for bacterial growth, adhesion, and protection. The gut microbiota and mucosal barrier have a symbiotic relationship, where the mucosal barrier helps the bacteria thrive and the gut microbiota contributes to the health of the mucosal barrier.4 Tight junctions act like gatekeepers, regulating the passage of substances between the cells. Disturbances in the gut microbiota can cause abnormalities in the membrane by loosening the tight junctions. When these tight junctions become vulnerable, the intestinal barrier is compromised allowing larger molecules to pass through. This can contribute to dysbiosis and then evolve into ‘leaky gut syndrome’.5 

Furthermore, an imbalance in the microbiota can cause metabolic disorders and increase central appetite, which can lead to diseases like obesity. As a result, the gut microbiota plays a huge role in both healthy and disease states. Therefore, it is important to create a gut environment that fosters healthy gut microbiota.2 Healthy gut microbiota is considered healthy when it is highly diverse, whereas a microbiome that lacks diversity has been associated with various diseases.2 

In a nutshell, a healthy microbiome is dependent on its ability to be resistant to stress, resilient to external (pharmaceutical, dietary) or internal (age) changes and the ability of the microbiome to recover after changes like this have affected the microbiome.6 

Factors that affect the gut microbiota 

The composition of a microbial community depends on the person, but it can be affected by exogenous (outside the body) and endogenous (inside the body) aspects.4 

Figure 1: A diagram showing the various exogenous and endogenous factors that can affect the gut microbiota at the top of the image, while the types of diseases that dysbiosis and leaky gut syndrome can cause, are shown at the bottom. The diagram of the intestinal barrier shows the stages of the intestinal barrier; eubiosis (balance between good and bad bacteria), dysbiosis and leaky gut syndrome.5

Exogenous factors

Your gut microbiota is mostly affected by exogenous factors like diet, lifestyle, stress, medications, alcohol consumption and environment.7 

The composition of your microbiota starts when you are a fetus, as microbiota exist in the placenta, amniotic fluid, umbilical cord blood, and meconium. These maternal microorganisms play a role in the establishment of the child’s microbiota.2 The GI tract is very quickly colonised after birth by events such as illness, antibiotic treatment and changes in diet.8 Your gut microbiota composition can also be affected by whether you were delivered vaginally or via Cesarean section (C-section). The microbiota of infants delivered vaginally contains a high abundance of lactobacilli during the first few days, as a result of the high load of lactobacilli in the vaginal flora. The faecal microbiota of vaginally delivered infants has been shown to have a 72% resemblance to their mother’s faecal microbiota, whereas babies delivered by C-section only had a 41% resemblance to their mother’s faecal microbiota.8 However, there is a ‘window of opportunity’ in the early life of a child, during which time the composition of the intestinal microbiota can still be ‘re-programmed’ through nutritional interventions such as breastfeeding. The timing and selection of the first solid foods are also factors that have a significant effect on the correct development of the gut microbiota. This length of the ‘window’ period is a matter of debate but is most likely from conception until the age of 2–3 years old.9 

A prominent aspect that can affect the composition of the community is one’s eating pattern. There is evidence that dysbiosis (an imbalance between good and bad bacteria) can be caused by a Western diet. The Western diet is characterized by high intakes of pre-packaged foods, refined grains, processed meat, high-sugar drinks, candy, salt, fried foods, high-fat dairy products, and high-fructose products. This diet can cause dysbiosis as it allows for the growth of gram-negative bacteria, which increases local inflammation and intestinal permeability.3 Antibiotics can affect the composition of the gut microbiome is as they decrease the diversity of bacteria and can disrupt the balance between the ‘good’ and ‘bad’ bacteria.1 A course of antibiotics can affect an individual’s gut microbiome differently depending on the type of antibiotics, age, diet and how many times they have taken antibiotics in the past. However, even a single use of antibiotics can result in dysbiosis.1

Endogenous factors 

Our genetic makeup influences our gut microbiota as it can affect aspects of our physiology and immune response that then impact the conditions available for microbial colonisation.10 For example, genes can influence the production of mucus in the gut lining and variations in genes related to mucus production can affect the ability of certain gut microbiota to establish and maintain a stable community affecting the composition of the microbiome. However, environmental factors have a more significant impact on the composition of the microbiome. The percentage of microbiome heritability is estimated to be below 2%, whereas more than 20% of the variation is related to diet and drugs amongst other factors.2 


We must understand the intricate relationships between gut microbiota and human health, as it offers valuable insights into managing and preventing a wide range of diseases and conditions, as well as promoting overall well-being. Your gut microbiota is a pivotal element of your health and therefore, should be nourished and protected from harmful exogenous factors that can have a negative impact.

So, what is the take away message?

The gut microbiome is a diverse community of microorganisms within the gastrointestinal tract, which produces a range of bioactive substances, influencing gene expression, immune function, and metabolic processes. Their pivotal role in regulating metabolism makes a healthy gut microbiota crucial for overall health. While genetic factors play a part, environmental influences, such as diet and medication, have a more substantial impact on gut microbiome composition. Dysbiosis, an imbalance between good and bad bacteria promotes inflammation and intestinal permeability. This can result in leaky gut syndrome, which is associated with various diseases.

Liviana™  Extra Virgin Olive Oil

Nestled in a beautiful valley on the slopes of the Stellenbosch Mountains lies our olive grove where we delicately handpick our organic olives in small batches. Each assemblage is carefully crafted with our unique cold extraction method and gently infused with just the right amount of the purest premium, organic CBD from the United States of America. At Liviana™ we are committed to exceptional quality, guaranteeing only the finest organic extra virgin olive oil – read more here.

You can purchase LivianaTM Extra Virgin Olive Oil here.

  1. Leong KSW, Derraik JGB, Hofman PL. 2017. Antibiotics, gut microbiome and obesity. Clinical Endocrinology, 88(2):185–200. Available here.
  2. Liu BN, Liu XT, Liang ZH, et al. 2021. Gut microbiota in obesity. World Journal of Gastroenterology, 27(25):3837–3850. Available here.
  3. Macchione IG, Lopetuso LR, Ianiro G, et al. 2019. Akkermansia muciniphila: key player in metabolic and gastrointestinal disorders. European Review for Medical and Pharmacological Sciences, 23(18):8075–8083. Available here.
  4. Castaner O, Goday A, Park YM, et al. 2018. The gut microbiome profile in obesity: A systematic review. International Journal of Endocrinology, 2018:1–9. Available here.
  5. Vincenzo FD, Gaudio AD, Petito V, et al. 2023. Gut microbiota, intestinal permeability, and systemic inflammation: a narrative review. Internal and Emergency Medicine. Available here.
  6. Lloyd-Price J, Abu-Ali G, Huttenhower C. 2016. The healthy human microbiome. Genome Medicine. Apr 27;8(1). Available here
  7. Sadagopan A, Mahmoud A, Begg M, et al. 2023. Understanding the Role of the Gut Microbiome in Diabetes and Therapeutics Targeting Leaky Gut: A Systematic Review. Cureus. Jul 8;15(7):e41559. Available here.
  8. Thursby E, Juge N. 2017. Introduction to the human gut microbiota. Biochemical Journal, 474(11):1823–1836. Available here.
  9. Arboleya S, Suárez M, Fernández N, et al. 2018. C-section and the neonatal gut microbiome acquisition: Consequences for future health. Annals of Nutrition and Metabolism, 73(3):17–23. Available here.
  10. Lopera-Maya EA, Kurilshikov A, van der Graaf, A, et al., 2022. Effect of host genetics on the gut microbiome in 7,738 participants of the Dutch Microbiome Project. Nature Genetics, 54(2), 143–151. Available here.
Spread the health, every byte counts
Nicola Royce

Nicola Royce

Registered Dietitian, Postgraduate Diploma Diabetes

Leave a Reply

M2Biome_HorizontalLogo - PurpleTagline - NoBackground-01-01
Our mission is to offer evidence-based, sustainable products that enhance health, performance, and longevity, while providing education to empower informed nutritional choices and lifestyle.

Find us

Unit 1, Mason’s Press, 7 Ravenscraig Rd, Woodstock, Cape Town, 7925
Call us: +27 66 393 0187
sign up for our


Will be used according to our Privacy Policy

Copyright © 2023 M2Biome, All rights reserved

Coming Soon to M2Biome

Artificial Intelligence & Personalised Nutrition

M2Biome will be bringing machine learning to develop personalised nutrition plans for individuals to achieve optimal health.