What are the causes of IBS?

What is IBS?

Irritable bowel syndrome (IBS) is an incredibly common condition. It is the most common condition I and most other nutritional therapists see in clinic. Interestingly, everyone who comes in with ‘IBS’ or IBS-like symptoms all experience a different set of symptoms.

Symptoms can include constipation, diarrhoea, alternating constipation and diarrhoea, flutalence, bloating, pain, belly rumbling, and urgency. Some people suffer every time they visit the loo, some know exactly when to expect an ‘episode’, whilst others cannot predict and it almost seems random.

The way the symptoms occur can certainly help you identify the cause, however, very often there are multiple factors involved and that’s when professional support and sometimes testing is useful.

Below are just some of the possible causes of IBS:

Food intolerance

A food intolerance is literally where the body is unable to tolerance the presence of certain foods in the body. In some cases this occurs when a digestive enzyme, needed to breakdown the food, is missing. In other cases, the poor health of the gut leads to partially digested fragments of foods entering the blood stream, which can cause an immune reaction. Food intolerances are different to allergies, which have a fairly immediate reaction. Food intolerances tend to occur over the course of a few days and this can make it difficult to identify the exact food(s) causing the issue.

SIBO (small intestinal bacteria overgrowth)

Some foods, known as FODMAPs, ferment in the gut causing bloating, diarrhoea and pain. Symptoms can often seem random and uncontrollable. This complication occurs when the bacteria that is normally present in the large intestine is able to overgrow in the small intestine, where there in normally much fewer bacteria. This normally occurs due to poor digestion or low stomach acid.

Poor digestion

As we age the pancreas is less able to produce pancreatic enzymes and production of bile becomes lessened too. Bile and pancreatic enzymes are important for the digestion of fat and protein. Symptoms in this case usually occur after eating rich or spicy foods. Low stomach acid also results in poorly digested foods and malabsorption of nutrients. This can be caused by medications, stress, poor diet, and malnutrition. It’s easier to stimulate the achieve the proper production of stomach acid, bile and pancreatic enzyme with simple dietary interventions.


A stimulant is anything that triggers the production of stress hormones. The five biggest culprits for this are alcohol, caffeine, sugar, stress and smoking. All of these things increase production of stress hormones, which leads to decreased gut transit time (makes you need the toilet sooner). It’s very common for stress or anxiety to cause an upset stomach and if you are one of these people then avoiding the other stimulants is important too.

Imbalanced gut bacteria

Stress, poor diet, alcohol, poor quality sleep, problems higher up the digestive tract, and antibiotics can all disrupt the balance of gut bacteria. Furthermore, if you were not breast fed or if you were born by c-section, you may have started life with sub-optimal gut bacteria. When gut bacteria get into this unbalanced state, they can produce high levels of toxins and process foods improperly too. These can both lead to various uncomfortable symptoms.


A parasite is a micro-organism that feeds off it it’s host. It’s different to the bacteria because we need the bacteria for proper gut function, but a parasite is just a hindrance. Parasites can be picked up from swallowing dirty water or eating uncooked food (particularly meat). Symptoms can seem random.

So how do you know what is causing your IBS?

Keeping a food and symptom diary is the best place to start. This may help you identify patterns in you symptoms. In all cases you can overcome IBS; you just have to find out what the root cause is! It’s also important to note that removing the cause will rarely be enough to resolve symptoms, as you’ll also need to heal the damage that has occurred in the gut too!

Seeking professional advice is very often the best way to address the problem. I specialise in digestive health and can often recognise a pattern in the symptoms, which means I can recommend the best thing to try first. I also have a huge variety of lab tests available, that can help us understand what is going on inside you gut and get to the root cause of your IBS.

I work with clients within my Essex and Suffolk clinics and also via phone and Skype, to help them gain control of their health.