3 Underlying Causes Of IBS Symptoms

3 underlying causes of IBS symptoms

If you suffer from IBS, I'm sure you'd love to know more about the root causes of IBS symptoms. Whether you've been diagnosed with IBS or not,  gastro-intestinal (GI) issues can make you feel miserable and disrupt your everyday life. I know, I've been there, and I'm here to help you heal your gut.

First, IBS (Irritable Bowel Syndrome) is the catch-all diagnosis that is given to people who are experiencing GI system symptoms, usually chronic, that are not being caused by a known GI condition or disease.

Sadly, many people suffer IBS symptoms in silence and resolve themselves to accepting it as something they have to live with. If this is you, trust me when I say, there are many ways to improve your gut health, but first it's crucial to identify the root cause of your unhappy gut.

3 root causes of IBS symptoms

There are lots of processes happening in your system during digestion. Any disruption can have unpleasant consequences. You may have low levels of digestive enzymes, stomach acid or bile, or low levels of healthy bacteria and high numbers of unhealthy bacteria in your gut. And your eco-system of gut bacteria may not be residing in the right place. Let’s look at these in more detail.

1. Insufficient gastric juices - enzymes, stomach acid and bile

The main digestive enzymes, Amylase, Protease and Lipase to help you digest carbohydrates, proteins and fats, are produced in the pancreas and small intestine, with small amounts from your salivary glands and the stomach.

There can be any number of reasons why your digestive enzymes may be low. One of which is age. As our production of digestive enzymes falls, our ability to fully breakdown food lessens.

Excessive gas, pain and bloating in the intestines can be due to inadequate protein digestion (causing some foods to ferment), or an inability to break down sugar and carbohydrates fully.

When food isn’t broken down properly, the formation of gas from undigested food particles will occur. Functional GI conditions like Small Intestine Bacteria Overgrowth (SIBO) and Leaky Gut Syndrome can also impact enzyme production in the intestine through inflammation and damaged cells.

Your stomach acid - hydrochloric acid (HCL) needs to be at the correct acidity level to digest your food properly. If your pH levels are too high (alkaline) or too low (too acidic) your digestion will suffer.

Low levels of stomach acid can result in undigested food particles in your stools, gas and bloating, as well as overgrowths of opportunistic bacteria and yeast, like Candida. These are all causes of IBS symptoms.

Bile has a similar impact on digestion to enzymes and stomach acid. If the gallbladder becomes clogged with stones or bile becomes too thick, you may experience extremely uncomfortable bloating and poor fat metabolism.

2. Imbalanced gut microbiome (aka gut dysbiosis)

100 trillion bacteria live inside us, forming an internal world known as “The Microbiome”. There are over 1000 different species living within the microbiome and each can have an impact on our health. In fact, so important is the microbiome, scientists believe it is not possible to be healthy without healthy gut flora.

In the digestive tract, there are trillions of healthy and unhealthy bacteria that compete, and when “bad bacteria” outweigh the good for one reason or another, an imbalance leading to causes of IBS symptoms, like abdominal pain, diarrhoea, constipation, bloating and excessive gas.

The microbiome in your gut consist of different bacteria, fungi and viruses. They form the majority of your immune system, acting as a line of defence to protect you from invading microbes - the bad guys like parasites. They are also fundamental to your digestion, breakdown of food and your absorption of nutrients.

There are many reasons why your gut ecosystem might not be as healthy as it should. Often the bad bacteria outweigh the good bacteria for one reason or another. These bad guys then impact digestion and absorption - cue gas, bloating, pain, diarrhoea and constipation.

Other ways to wipe out your gut microbes is through lifestyle and environmental factors such as stress, smoking and eating a highly processed diet with little fibre.

3. Bacterial overgrowth in the small intestine (SIBO)

The causes of IBS symptoms can often be due to SIBO. SIBO is more prevalent than previously believed, and it occurs in many people suffering from IBS and certain other underlying conditions. It’s defined as excessive bacteria in the small intestine, or small bowel (1)

While bacteria naturally occur throughout the digestive tract, in a healthy digestive system, the small intestine has relatively low levels of bacteria, as it’s supposed to be at highest concentrations in the colon.

When in proper balance, the bacteria in the colon helps digest foods and the body absorb essential nutrients. However, when bacteria invade and take over the small intestine, it can lead to poor nutrient absorption, vitamin deficiency, symptoms commonly associated with IBS, and may even lead to damage of the stomach lining.

As food passes through the small intestine, the bacterial overgrowth interferes with the healthy digestive and absorption process. The bacterium associated with SIBO actually consumes some of the foods and nutrients, leading to unpleasant SIBO symptoms, including gas, bloating, pain, and potentially diarrhoea and constipation.

There can be several causes of SIBO - low stomach acid, altered gut motor function, visceral hypersensitivity, antibiotic use, proton pump inhibitor medications, impaired immune function and post-surgical or post-injury abdominal adhesions.

The most common symptoms of SIBO include gas and bloating after meals, burping or reflux, chronic diarrhoea or constipation, or an alternating of both, and abdominal discomfort or pain.

Working out the root cause(s) of IBS

Because there's so many reasons for the above GI problems, it’s really important to identify and tackle the underlying cause.

As everyone is unique, what may appear to be a common symptom on the surface, can very well stem from a different root cause to someone else experiencing the same symptom.

For example, is your gas, pain and bloating due to motility and structural issues? If this is the case, it's likely visceral manipulation can help. Or is the cause of IBS symptoms due to low stomach acid levels that need restoring to kill off harmful bacteria? Or do you have insufficient enzyme production to break down nutrients from your food?

It’s quite likely there is more than one reason for the causes of IBS symptoms, as we know everything in the body is connected.

With functional GI testing you get to see exactly what's working well and what's not working so well, together with what microbes are residing or not residing in your gut's large intestine. As I'm sure you can imagine, the overall picture differs greatly from one individual to another.

Help with your IBS

If you want to improve your gut health and would love some help to identify and treat the root causes of IBS symptoms, check out my Gut Health Plan, or Contact Me for a chat about how we can optimise your gut function and subsequently improve your overall health.

Non-digestive health issues can also be linked to poor gut health, so even if you don't experience IBS symptoms it doesn't mean that your fatigue, excess weight gain, weak immunity or skin problems aren't down to the state of your gut health.


I hope you've found this blog post helpful, and do comment below if you wish to share your own experiences or insights.

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Meet Nicola - blog posts

Meet Nicola

Hi, I'm an Integrative Nutrition Health Coach, Pain & Stress Management Therapist, and Certified Functional Medicine Practitioner.

I help people elevate their mind and body health by addressing diet, nutrition and lifestyle symptoms. Let's work together to optimize how you feel and function.

Gut Health Plan

Gut Health Plan

90 Days of healing to optimise your gut function. Improving your gut health isn't just beneficial for digestive complaints. Did you know that 60 - 80% of your immune system and 90% of your feel-good hormone serotonin, resides in your gut?