Deforestation of the ‘Gut Rainforest’: Chronic Constipation

  • 1st Revision: Isobel Lester
  • 2nd Revision: Alex Jasnosz
  • 3rd Revision: Tricia Lai

We have all been there. Inundated with anticipation, held in with regret. The stomach churns that course through each cell of our beings. Constipation is an uncomfortable experience, to say the least. Our bodies are finely tuned machines with necessary ‘input’ and ‘output’ systems, so without a functional output mechanism, the finely tuned machine begins to sound somewhat out of pitch. 

What is constipation?

Functional constipation, or chronic idiopathic constipation, is characterised by ‘decreased bowel movements and/or hard stools. It is diagnosed by the process of elimination: before reaching this diagnosis, other reasons, for example, bad diet, medications, and lack of exercise, need to be ruled out. Current treatments include laxatives such as Senna and Lactulose. However, their side-effects can be bothersome, so long-term use is generally not recommended1.

Until recently, constipation was studied by looking at how well the intestine works. Recently, there has been a spark in scientific interest in the vast and wonderful microorganisms living in our gut (known as the gut microbiota or flora) and, more specifically, what happens when these organisms become imbalanced (dysbiosis)1.

The gut microbiota

From the moment we enter this world, millions of microorganisms (bacteria, yeast and fungi) start to ‘colonise’ our skin, gut, mouth etc. It is surreal to think over one million microorganisms have made a home on/inside of us, each paying rent in their own respective ways to defend us from the ‘bad’ microorganisms that cause diseases. ‘Although the anthropocentric concept of life has concealed the function of microorganisms inside us, the important role of gut bacterial community in human health is well recognised today’1, gut microbiota has recently been coined a ‘virtual organ’2 - our understanding has grown however there is still much untouched ground. To understand why dysbiosis allows for gastrointestinal havoc, we need to know how things work when they’re good; we must delve into the functionality of the symbiotic relationship we have with our gut microbiota.

The function of gut microbiota

Our gut microbiota assists human function in a variety of different ways. As part of the nutritional system, bacteria in the intestine produce vitamin B12 (required for the proper function of the brain and spinal cord) and some short chain fatty acids (e.g. butyrate). Short chain fatty acids allow energy to be taken up from dietary fibres that would otherwise not be taken up. For example, the breakdown of bacteria in cheese produces free amino acids (which cells use as building blocks to make proteins), others will repair any leaky wall that turns up (in line with the renting analogy - they would be excellent tenants!). It was reported by a paper in the 1980s already, that 70% of energy taken up the cells in the intestines are derived from butyrate3

What causes gut flora imbalances?


Dysbiosis of the gut microbiota can be due to many causes such as: dietary changes, chemical consumption (e.g. lingering chemicals on unwashed fruits), excess alcohol use, poor dental hygiene or unprotected sex. In addition, high stress levels can play a role in weakening the immune system which, in turn, will have an effect on the stability of our gut ecosystem. It is important to note the multifactorial nature of dysbiosis, for example stress can have an impact on what an individual decides to eat or how much someone decides to drink which could lead to poor dietary intake or excess alcohol use. There is also some research into the effect of initial gut colonisation in early life (we are born germ-free, though this does not last very long). A study in 2016 found that children with functional constipation ‘are more likely to have a history of delivery via cesarean section and a shorter duration of breastfeeding compared to controls with no history of constipation’4.


Antibiotics can have both positive and negative effects on our gut microbiota. They defeat infections by killing bacteria. The issue with these drugs is that they cannot differentiate between helpful and harmful bacteria. Long-term or regular antibiotic use has been linked to constipation due to antibiotics ‘wiping’ out gut flora leading to less of those helpful microorganisms present to help with digestion. Interestingly, antibiotics have also been involved in the treatment of gastrointestinal issues. If you have been on antibiotics for a long time, or find yourself being prescribed them quite often, discuss with your GP or local pharmacist steps you can take to take care of your gut4,5.

Improving gut health

In recent years other ‘biotics’ have been gaining much traction. Probiotics, prebiotics and synbiotics have also been researched and identified as possible treatments for chronic constipation. Probiotics are live microorganisms that promote health benefits - lactobacillus and bifidobacteria are the most popular. Prebiotics are carbohydrates that our body can not break down; they work by increasing the activity levels of the gut microbiota. Synbiotics are a mixture of probiotics and prebiotics. There are also faecal microbiota transplants - which is essentially a ‘poo’ transplant. Research in the poo field indicates positive outcomes for all these treatment options. However, their trials often included small samples and each is testing different types of bacteria - this makes it difficult to ‘pool’ research findings together. It becomes even more tricky, when you realise that our gut microbiota is as individual as a fingerprint. Future studies are hoping  to look at specific microorganisms and their combinations within specific demographics. If we are able to identify which specific microorganisms are present in our particular constipated population (and this could be different for different ages, ethnicities, etc.), we will then be able to design specific ‘biotic’ treatments to tackle and correct the imbalance causing the issue 2,5.

There will be a lot more said about our buzzing companions in the coming years. There is already so much to be said about the mechanisms by which they survive and allow us to do the same. This article should bring to light the importance of gut health, other ways to keep our friends healthy is exercise, water, a good diet including ‘good gut’ foods such as live bio yoghurt, kimchi, sauerkraut, miso, and kombucha!


  1. Noergaard M, Traerup Andersen J, Jimenez-Solem E, Bring Christensen M. Long term treatment with stimulant laxatives - clinical evidence for effectiveness and safety? Scand J Gastroenterol. 2019 Jan;54(1):27–34.
  2. Evans JM, Morris LS, Marchesi JR. The gut microbiome: the role of a virtual organ in the endocrinology of the host. Journal of Endocrinology [Internet]. 2013 Sep 1 [cited 2021 Dec 13];218(3):R37–47. Available from:
  3. Albert MJ, Mathan VI, Baker SJ. Vitamin B12 synthesis by human small intestinal bacteria. Nature [Internet]. 1980 Feb [cited 2021 Dec 13];283(5749):781–2. Available from:
  4. Martín R, Miquel S, Ulmer J, Langella P, Bermúdez-Humarán LG. Gut ecosystem: how microbes help us. Benef Microbes. 2014 Sep;5(3):219–33.
  5. Ohkusa T, Koido S, Nishikawa Y, Sato N. Gut microbiota and chronic constipation: a review and update. Frontiers in Medicine [Internet]. 2019 [cited 2021 Dec 13];6:19. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Zahra Boukhari

Master of Pharmacy, University of Brighton, UK

Master of Pharmacy graduate. Currently gaining experience in a variety of healthcare settings before commencing her foundation year. Interested in research within the fields of psychopharmacology and psychedelic medicine.

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