What is Dysbiosis?

What is Dysbiosis?

Optimal fertility starts with nurturing your microbiota - the tens of trillions of microorganisms that live in our gut.

Your gut microbiota is made up of microbes that promote and dampen inflammation, and it plays a central role in your reproductive health.

One reason for the strong connection between your gut microbiota and reproductive health is that your resident microbes can influence metabolic endotoxaemia.

Metabolic endotoxaemia play a role in difficulty conceiving and early pregnancy loss. You can promote a gut microbiota that will limit any metabolic endotoxaemia but before we find out how to do this, let's find out more about metabolic endotoxaemia and its role in fertility.

What is Dysbiosis?

If your microbiota are out of balance, inflammation and oxidative stress are elevated. This has a negative impact upon the development of eggs and sperm, and pregnancy progression. 

Dysbiosis, or an imbalance in your gut microbiota, can impair reproductive health and there are a number of contributors to dysbiosis. The balance in good and bad microbes can be triggered by stress, antibiotic consumption, consuming processed foods, low dietary fibre intake, sleep disturbances and physical inactivity.

Dysbiosis is a hallmark of conditions affecting fertility such as:

  • ⚈ polycystic ovary syndrome (PCOS)
  • ⚈ endometriosis
  • ⚈ low testosterone in males
  • ⚈ oestrogen driven conditions
  • ⚈ obesity
  • ⚈ inflammation and oxidative stress, seen in unexplained infertility

Maintaining the Front Line - the Gut Barrier

Our gut is essentially a physical barrier to food, fluid and pathogenic (disease causing) organisms that transit through the gut. One side of the gut is exposed to food and the other side is where the 'control' centre is. This is where you will find all of your nerves, the blood supply and lymphatic vessels.

There are a few different cell types in the gut including enterocytes that play a role in absorption, M cells that sense foreign particles and paneth cells that have antimicrobial properties.

Another component of the ‘physical’ barrier of the gut is the layer of mucus in the gut lumen. This is a hydrophobic gel made up of complex carbohydrates. The mucus layer increases in thickness from the small intestine to the large intestine and it is a very important component of keeping the gut healthy.

Goblet cells secrete mucins that make the mucus layer and they also secrete bioactive components that stabilise the mucins. In disease states associated with excess inflammation, this protective mucus layer gets broke down and is much thinner or even absent in sections of the gut.

A Permeable Gut - Fertile Consequences

Our microbiota play a key role in extracting energy from food, immune tolerance, prevention of the colonisation of pathogenic microorganisms and importantly enhancing the integrity of the epithelium (how well our gut cells stick together).

As technology has enabled us to identify and quantify our gut microbiota, we are recognising how essential it is to maintaining a functional, healthy gut.

Our gut microbiota contains tens of trillions of microorganisms, including at least 1000 different species of known bacteria.

They produce the key signalling molecules of short chain fatty acids. These organic acids,  primarily acetate, propionate, and butyrate, are produced in the gut by bacterial fermentation of undigested dietary carbohydrates, specifically resistant starch and other dietary fiber and, to a lesser extent, dietary and endogenous proteins.

An imbalance in your gut microbiota weakens the integrity of the gut wall. Dysbiosis leads to an increase in inflammation and these signals disrupt the tight junction proteins that hold our gut cells together.

When cells of the gut are disrupted there is an increase in gut permeability which allows for compounds such as LPS (lipopolysaccharide) to cross over into the blood stream. LPS is a potent driver of inflammation.

When components from the gut lumen cross over the disrupted barrier, this can lead to metabolic endotoxaemia. An increase in circulating levels of bacterial endotoxin or LPS contribute to inflammation in the ovary, reduce progesterone production and increase levels of sperm DNA damage. This ultimately results in poor quality eggs and sperm.

Increased circulating levels of LPS are found in:

  • ⚈ Inflammation and Oxidative Stress
  • ⚈ Embryonic cell death
  • ⚈ Implantation failure
  • ⚈ Oviduct inflammation
  • ⚈ Reduced sperm production
  • ⚈ PCOS
  • ⚈ Endometriosis

This disruption of the gut barrier also has negative consequences for pregnancy, increasing systemic inflammation and insulin resistance in pregnancy.

Reinforcing the intestinal barrier reduces metabolic endotoxin levels improving egg and sperm quality, implantation potential and pregnancy health.

Strengthening the Gut Barrier

A diverse microbiota reinforces the gut barrier, making it stronger and more resistant to damage and the impacts of toxins like LPS.

Creating a fertile friendly depends on the provision of microbiota-accessible carbohydrates that are found in dietary fibre. Essentially, eating prebiotic fibre each day can shape your microbiota for enhanced diversity.

Prebiotics are nondigestible, fermentable foods that are fuel for your beneficial microbes living in your gut. Prebiotic fibre has distinct physical and chemical properties which interact with the microbiota of your gut, shaping your fertility in positive ways. One of these is through the production of butyrate and you can read more about that here.

Other benefits of taking resistant starch to increase the diversity of your microbiota include:

  • ⚈ Reduced body fat and increased fullness, promoting weight loss
  • ⚈ Increased insulin sensitivity to improve metabolic health
  • ⚈ Improved antioxidant enzyme activity to fight oxidative stress
  • ⚈ Reduced inflammatory protein production

How do you Create a Fertile Gut?

Aim to have a variety of different fibre types every day. Make sure these include quality resistant starch and fibres that are proven prebiotics

If you are not getting a great variety of fibres or eating enough whole, fresh foods every day, Fertile Gut is a super easy way to add these to your day! Our scientifically formulated blend contains proven prebiotics supported by essential fatty acids to support reproductive health.

Follow us @fertilegut for some recipes and tips to boost your fibre intake, microbiota diversity and reproductive health!



  1. Li Z, Zhang D, He Y, Ding Z, Mao F, Luo T et al. Tohoku J Exp Med. 2016;238(2):105-12. doi:10.1620/tjem.238.10
  2. Jaiswal YK, Jaiswal MK, Agrawal V, Chaturvedi MM. Fertil Steril. 2009;91(5 Suppl):2095-103. doi:10.1016/j.fertnstert.2008.04.050.
  3. Deb K, Chatturvedi MM, Jaiswal YK. Gynecol Obstet Invest. 2004;57(4):224-32. doi:10.1159/000076761.
  4. Cerny KL, Ribeiro RAC, Li Q, Matthews JC, Bridges PJ. Reprod Fertil Dev. 2018;30(4):600-8. doi:10.1071/RD17241.
  5. Zhu Q, Zhou H, Zhang A, Gao R, Yang S, Zhao C et al. PLoS One. 2016;11(1):e0145337. doi:10.1371/journal.pone.0145337.
  6. Azuma Y, Taniguchi F, Nakamura K, Nagira K, Khine YM, Kiyama T et al. Am J Reprod Immunol. 2017;77(4). doi:10.1111/aji.12631.
  7. Thompson SV, Hannon BA, An R, Holscher HD. Am J Clin Nutr. 2017;106(6):1514-28. doi:10.3945/ajcn.117.163246.
  8. Guess ND, Dornhorst A, Oliver N, Bell JD, Thomas EL, Frost GS. Nutr Metab (Lond). 2015;12:36. doi:10.1186/s12986-015-0033-2.
  9. Eshghi F, Bakhshimoghaddam F, Rasmi Y, Alizadeh M. Clin Nutr Res. 2019;8(4):318-28. doi:10.7762/cnr.2019.8.4.318.
  10. Swann OG, Kilpatrick M, Breslin M, Oddy WH. Nutr Rev. 2019. doi:10.1093/nutrit/nuz072.



About the Author

Hi, I'm Dr Cecilia Kitic founder of Fertile Gut and The IVF Project. We can't wait to help support you on your journey to optimal reproductive health! Having spent over 20 years researching in the areas of immunonutrition, physiology, biochemistry and gut health we now get to translate science into practice, sooner. Our gut microbiome provides a foundation for our fertility and reproductive health and with our scientifically crafted natural formulations you will be creating a Fertile Gut!

You May Also Like

1 of 3