Understanding Irritable Bowel Syndrome

Welcome to Understanding Irritable Bowel Syndrome

You are reading this because you have IBS or you know someone that does!

If your asking yourself “Do I know someone with IBS” the answer is most likely “Yes”. 

With almost 1 in 5 people suffering from IBS its likely that some of your close family or friends do!

Once you’ve had a camera up your bottom and various blood tests it can come as a relief that your diagnosis isn’t something more life threatening. 

Anxious,Overwhelmed, Confused and Worried are common terms expressed by some of my patients. 

You’re likely to have a lot of questions that your tapping into search engines. 

  • What actually is IBS?
  • How do I manage IBS?
  • What do I eat? 

The additional anxiety and worry is unlikely to make your symptoms any better!

Understanding Irritable Bowel Syndrome does exactly what it says on the tin. 

This post will help you understand IBS and hopefully answer some of those burning questions. 

Lets begin.

What is IBS?

“Irritable Bowel Syndrome is a gastrointestinal disorder characterised by altered bowel habits in association with abdominal discomfort or pain in the absence of detectable structural and biochemical abnormalities”.(1)

Irritable Bowel Syndrome can be characterised by the presence of the following symptoms:

  • Diarrhoea
  • Alternating bowel habit
  • Abdominal discomfort
  • Bloating and distension
  • Urgency to visit the loo
  • Faecal Incontinence

Symptoms range from diarrhoea to constipation, a combination or the two along with abdominal pain and discomfort existing alongside abdominal distension(2).

IBS is sub grouped into predominant bowel pattern –

IBS with constipation-hard or lumpy stools > 25% and loos or watery stools < 25% of bowel movements
IBS with diarrhea-loos or watery stools > 25% and hard or lumpy stools stools < 25% of bowel movements
Mixed IBS-loos or watery stools > 25% and hard or lumpy stools stools > 25% of bowel movements
Unsubtyped IBS-insufficient abnormality of stool consistency to meet criteria for IBS-C,D or M


The degree of symptoms along with variety and frequency varies immensely between individuals.

Some may suffer excruciating chronic pain whilst others have intervals which can last from weeks to months(3).

For example episodes of constipation followed by urgent, explosive diarrhoea.

Diagnosing IBS

There is currently no biochemical, histological or radiological diagnosis of IBS, while the diagnosis of IBS being based mainly on symptom assessment(2).

See also  Probiotics

Rome IV Criteria. 

Recurrent abdominal pain, on average, at least 1 day per week in the last 3 months, associated with  ≥2 of the following: 

  1. Related to defecation 
  2. Associated with change in stool frequency 
  3. Associated with change in stool form (appearance)

Criteria should be fulfilled for at least 3 months with symptoms onset ≥6 months prior to diagnosis. 

Upon presenting these symptoms, your Gastroenterologist may want to investigate further if you have any of the following red flag indications.

  • Weight Loss
  • Rectal Bleeding
  • Anaemia
  • Inflammatory markers

The above symptoms are NOT suggestive of IBS and must be investigated further by your Specialist Gastroenterologist.

A routine assessment can include a Colonoscopy, stool tests and blood tests which identify whether there is any inflammation.

Hopefully these investigations will rule out more serious conditions including:

  • Inflammatory Bowel Disease
  • Coeliac Disease
  • Cancer
  • Diverticulitus

Following these investigations, your consultant may come to the conclusion that there is no structural abnormalities to identify your symptoms.

This is likely to come as a sigh of relief when you’re told that your diagnosis is IBS and not life threatening.

It’s only weeks later when your symptoms return and you think of all the questions that you should have asked your consultant.

Who does IBS effect?

Irritable Bowel Syndrome is one of the most common gastrointestinal disorders. The percentage of patients seeking health care related to IBS approaches 12% in primary care practices and is by far the largest subgroup seen in gastroenterology clinics[1].

Figure2. Prevalence of IBS from Rome criteria.

This is a lifelong condition that can appear out of nowhere with no clues to what initially caused your symptoms. 

An estimated 5%-20% of the world population suffer from IBS, almost 1 in every 5.

More than twice as many women than men are affected by IBS although this prevalence could be down to women generally reporting more symptoms to their Doctor than their male counterparts. 

“Although a minority (10%-50%) of IBS patients seek healthcare, they generate a substantial workload in both primary and secondary care”[2]. COST OF IBS IN UK(REF).

Although age is not a contributing factor toward IBS, most presenting complains are between the age of 20-30 years. 

Why Do I Have IBS?

This is a difficult question to answer. 

No one actually knows exactly what causes IBS, however we do know that some factors can trigger or worsen symptoms.

  • Gastrointestinal infection 
  • Psychological
  • Increased sensitivity/ Visceral hypersensitivity
  • Altered gastrointestinal motility
  • Brain-Gut Interactions
  • Gut Flora Alterations
  • Intestinal Inflammation
  • Diet 
See also  Rome IV Criteria. What Type of IBS Do You Have?

Gastrointestinal Infection or Post Infective IBS is thought to affect 3-17% who have undergone an episode of gastroenteritis(5).

Most cases resolve after 6 months, however approximately 10% report persistent symptoms over this time(4).

Clinical features of Post Infective IBS include bloating, loose watery stools and urgency to defecate.

Psychological– Anxiety and anger can induce small bowel transit enhancing stool frequency.

Whereas depression and fear have the opposite effect and is more likely to delay colonic transit.

The “Brain-Gut Axis” refers to the interaction between the brain (central nervous system) and the intestinal tract.

Stress, emotions, and psychological problems can affect gut sensation, motility, and secretion.

Sensations within the gut can also affect the central nervous system leading to pain or to changes in mood or behaviour.

Abusive history, exaggerated consciousness, perfectionism and neuroticism is commonly reflected in personal features(5).

Visceral Hypersensitivity is the increased sensitivity of pain within internal organs.

This means that any changes in the gut including the buildup of gas or a large bowel motion can cause increased pain.

Diet and lifestyle

I don’t mean to disappoint , but diet is NOT the cause of IBS. 

Lets say for example, we had two people living in the same house, working at the same job, eating the same, one of those people could easily have IBS with the other having no problems at all. 

So what is causing IBS? No one really knows and therefore we can’t give you a definitive answer. 

What we do know is that there are a group of contributing factors, when managed can help symptoms and improve quality of life. 

Diet manipulation can significantly improve symptoms and advised by NICE as first line management of IBS. 

Adopting a balanced diet with regular meals and structure would be this first thing to implement. 

Over eating with large portions can result in stretching of the intestine causing pain, bloating as does going long periods without eating. 

Diet and nutrition should be assessed for people with IBS and the following general advice given.

  • Have regular meals and take time to eat.
  • Avoid missing meals or leaving long gaps between eating.
  • Drink at least 8 cups of fluid per day, especially water or other non caffeinated drinks, for example herbal teas.
  • Restrict tea and coffee to 3 cups per day.
  • Reduce intake of alcohol and fizzy drinks.
  • It may be helpful to limit intake of high fibre food (such as wholemeal or high fibre flour and breads, cereals high in bran, and whole grains such as brown rice).
  • Reduce intake of ‘resistant starch’ (starch that resists digestion in the small intestine and reaches the colon intact), which is often found in processed or re cooked foods.
  • Limit fresh fruit to 3 portions per day (a portion should be approximately 80 g).
  • People with diarrhoea should avoid sorbitol, an artificial sweetener found in sugar free sweets (including chewing gum) and drinks, and in some diabetic and slimming products.
  • People with wind and bloating may find it helpful to eat oats (such as oat based breakfast cereal or porridge) and linseeds (up to 1 tablespoon per day). [NICE,2008]
See also  Are You Getting Enough Vitamin D?

 How Do I Manage my Symptoms?

That all very much depends of YOUR symptoms. 

The free diet and symptom diary along with the symptom severity tool will help you identify the following:

  •  Identifying your symptoms
  •  Frequency of your symptoms
  •  Severity of your symptoms
  • Trend in your symptoms

There is no “one size fits all” approach towards managing IBS, therefore self-management should be encouraged.

Once you have identified your symptoms, you may want to steer your approach towards managing constipation which could include eating more fibre and drinking more fluids. 

Alternatively if constipation were an issue, the approach may be towards eating less fibre or less insoluble fibre and remain drinking fluids to minimise dehydration. 

Caffeine, milk products, wheat and various fruits can be known to worsen some symptoms. 

A Registered Dietitian can help go over your diet in more detail, increasing or decreasing fibre as well as caffeine, fatty foods and alcohol. 

Some people may require simple alterations to their diet whilst others may benefit from a more exclusive diet such as the low FODMAP diet.

The low FODMAP diet is an exclusion diet designed by Monash University in Australia. 

IBS sufferers are advised to make simple (first line) dietary changes which before considering the FODMAP diet. 

The FODMAP diet can be challenging as it excludes variety of foods and can be more costly when doing the weekly shop.  

Despite this, the FODMAP diet boasts a 76% improvement in overall symptoms, the FODMAP diet should be carried out alongside a Registered Dietitian.

Your Dietitian will help you adhere to the low FODMAP diet to ensure the best outcome whilst remaining nutritionally adequate.

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