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Constipation Root Causes

Updated: Mar 9, 2023

I see clients on a daily basis that have finally decided to tackle their constipation. Many have been labeled with an IBS-C diagnosis or functional constipation and given laxatives and vague advice to eat more fiber, do more exercise and drink more water. Although these things are very important for managing constipation, they only take you so far. There is almost always an underlying (and treatable!) cause for chronic constipation that needs to be addressed to fully overcome it.

This post is for everyone who has been ‘diagnosed’ with IBS-C or Functional Constipation (or self-diagnosed) and haven’t yet found the right education and/or courage to identify and treat their underlying root cause.

Here is a summary of what we are going to cover:

  • What is IBS-C and Functional Constipation?

  • What’s wrong with these definitions?

  • What’s the difference between a symptom and a root cause

  • The top 3 constipation root causes that your doctor probably isn’t considering.

Definition of IBS-C and Functional Constipation

Let’s get the definitions out of the way. As outlined in the Rome III diagnostic criteria:


1. Recurrent abdominal pain/discomfort for 3 or more days, that is associated with 2 or more of the following:

  • Improvement with defecation

  • Onset associated with fewer stools

  • Onset associated with harder stools

2. Lumpy or hard stools (Bristol Stool Form Scale 1–2) for ≥ 25% of defecation.


1. Two or more of the following symptoms:

Straining ≥ 25% of defecations

  • Lumpy or hard stools for ≥ 25% defecations

  • Sensation of incomplete evacuation for ≥ 25% of defecations

  • Sensation of anorectal obstruction/blockage ≥ 25% of defecations

  • Manual maneuvers to facilitate ≥ 25% of defecations

  • ≤ 3 defecations per week

  • Loose stools are rarely present without use of laxatives.

  • Diagnostic criteria for IBS not met.

What’s wrong with these definitions?

Besides these definitions being confusing because they basically have the same symptoms, the bigger problem lies in labelling constipation as a condition, rather than a symptom. This doesn’t help anyone to actually treat the problem, and instead leads those suffering with constipation thinking that they need to live with it. I’ve heard too many times, medical professionals telling their patients that some people just don’t have daily bowel movements and that this is normal, which is completely untrue!

What’s the difference between a symptom and a constipation root cause?

A symptom is the physical outcome you experience. Like constipation. A root cause is the reason that it is occurring. Constipation is a symptom and it has a reason (root cause) for happening. While you can manage the symptom with medications like laxatives, you can’t fix constipation simply by identifying that you have constipation. You can only fix constipation once you identify WHY you have constipation. More on this soon.

Laxative use is a common treatment for constipation, but they generally only work short-term. They can be a good management tool to use while you work on the root cause of your constipation, but long-term use will likely result in constipation (and gut health) progressively worsening, unless the underlying cause

So let’s get into the root causes. It’s not an exhaustive list by any means, but these are definitely the most common root causes of constipation I see in my practice.

Constipation Root Cause #1: Small Intestinal Bacterial Overgrowth (SIBO)

I’ve written a deep dive blog on SIBO, but here’s the short version. SIBO is characterised by an increased number and/or abnormal type of bacteria in the small intestine. Because these bacteria generally live in the large intestine, they are mostly species that ferment carbohydrates into hydrogen gas (H2) or archaea (not technically bacteria) that produce methane gas (CH4).

While both hydrogen and methane types typically result in abdominal bloating and distention, as with IBS sufferers, SIBO types are divided into one of three different categories; diarrhea-dominant, constipation-dominant or alternating variations of both.

The diarrhea-dominant SIBO is generally the result of carbohydrate-fermenting bacteria that produce hydrogen gas in the small intestine. The constipation sufferers, on the other hand, generally have archaea to blame. During the fermentation of carbohydrates, archaea feed off the hydrogen produced by bacteria and produce a by-product of their own; methane. As with hydrogen, methane gas in the small intestine will cause abdominal bloating, plus a much bigger problem – slowed transit time and ultimately, constipation, which further contributes to bloating.

Constipation Root Cause #2: Gut-brain Axis Issues

The enteric nervous system (ENS), sometimes called the “second brain,” governs digestion through hundreds of millions of nerve cells that report back to the brain. When the communication between the ENS and brain is interrupted or impacted, that can disrupt digestion and bowel movements, leading to constipation. One of the most common ways that this communication is disrupted is through unmanaged chronic stress and anxiety. Although stress is actually a good thing to experience in small doses (helps us to grow and learn), prolonged stress can lead to slow motility and therefore, constipation.

Constipation Root Cause #3: Imbalances in the gut microbiota (dysbiosis)

Individuals with constipation often have significantly different gut bacteria composition than non-constipated healthy people, with higher levels of methane producing microbes in their intestines, which slows intestinal transit time. Similar to SIBO, these methane producing microbes (archaea) can grow in abundance in your large intestine too. The difference between dysbiosis and SIBO is with dysbiosis these microbes are supposed to be there, they have simply overgrown in numbers that are higher than the norm. This usually happens because other microbe species in the gut are too low, which allows for these more problematic constipation causing species to overgrow.

How to find out your constipation root causes

-Testing to rule out conditions like SIBO. I routinely run SIBO breath tests with my constipated clients and more often than not, the results show abnormal production of methane gas. This is great news, as it provides a clear pathway for treatment.

-Doing a deep dive into when your constipation first started and what current diet and lifestyle factors may be further contributing to the problem. Taking care of any root causes for constipation is essential, but it is also very important not to overlook dietary factors, movement, sleep and fluid intake, which will often make the situation worse and prevent full recovery. Often there’s an initial trigger for developing the root cause (i.e. an episode of food poisoning or surgery that developed into SIBO, or the onset of anx

iety disorder that lead to gut-brain axis issues), but this will often lead to changes in diet and lifestyle intended to fix the symptoms experienced which unintentionally further contributes to constipation (restrictive diets and undereating are big factors here). You can read more about this concept called ‘the constipation cycle’ here.

The key takeaway is that there is always a reason you don’t have regular, complete or well formed bowel movements. There is no one-size fits all approach to treating constipation, but with the right help and understanding, it is possible to overcome it without having to rely on long-term laxatives.

Got questions about this? leave a comment below, or contact me here.

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