Skip to content

An update on Irritable Bowel Syndrome

IBS is a cluster of symptoms — including pain and a change in bowel habits — that lasts over six months. Each person has their own group of bothersome discomforts, which can make IBS difficult to diagnose.

Clients can discuss symptoms with their doctor, who will coordinate gastrointestinal investigations which are needed before the diagnosis of IBS is made.

Clients will tell you what IBS means for them and how severe the symptoms are. Just listening will help you gather information that will help you decide how to best support them.

People with IBS have often suspected food as a cause and often excluded foods they think give them symptoms, such as bloating and flatulence, although the suspect foods differ widely between individuals.

Foods often mentioned include the cabbage family of vegetables, and legumes. Some suspect gluten and others onion or garlic. Fruit, especially fruit juices, are often mentioned.


Where bloating is present, the FODMAPS diet must be considered.

The bloating may be followed by distressing distension which may increase until pain spasms occur. Bloating really interferes with life, with some people even needing a variation in clothes sizing over a day.

Passing wind is increased and it may also be smelly, and some have distressing burping too.

People may pass wind with bowel motions, resulting in bothersome ‘explosive’ motions. Some may experience loose motions while others may be constipated.

Now that more scientific studies have been done on the use of the FODMAPS diet, the role of diet has become better understood and more widely adopted as treatment for IBS.

IBS and food chemicals

In some people, food chemicals such as additives, salicylates, amines and glutamates also cause IBS symptoms, particularly gut pain. This pain is often lower crampy pain which may be annoying, through to pain as severe as bad menstrual pain, or even as bad as labour pains.

Pain may come on a few hours after eating, or at 2 am and disturb sleep for hours, or not for 24 hours after dining out. It may last until a bowel motion is passed.

Clients may comment that they have a wave of ‘feeling faint’ as the motion is passed. Some may feel ‘knocked flat’ after passing the bowel motion.

There is a range in the recovery time, from people who report they can keep working but are aware that they are ‘recovering’ after the bowel contraction, to others who need rest and time for the pain to resolve.

Bowel urgency is also common and may be so strong that no outing can be considered unless toilets are known to be nearby.

Food sensitive patients more often have frequent motions and this frequency is the most bothersome symptom for these patients. Bowel motions may be loose or normal in consistency, or they can vary.

Some patients report few symptoms on their usual at-home food, but if they dine out they often suffer symptoms afterwards. Others connect symptoms to spice, or what they call ‘rich food’, or to high fat foods. They may choose — even crave — foods such as chocolate, some high additive foods or soft drinks, or one particularly favourite sauce.

Clinical research has shown that the Low Chemical Diet reduces these symptoms in susceptible people.

IBS and diet therapy

Diet therapy is an important part of IBS treatment. Each person’s experience of IBS is individual, and people may have both types of symptoms, with suspect foods from both FODMAPS and food chemicals involved. For example, cabbage and chocolate may both be suspect.

Whole foods such as dairy or wheat may also be suspect. This may be related to the need for lactose limitation in dairy foods, or fructan minimisation in wheat-containing foods, or attention to dairy intolerance, or to non-coeliac wheat intolerance separately.

Based on the symptoms, an Accredited Practising Dietitian (APD) will decide on the dietary treatment. A combination of the two diets may be used, with the composition dependent on the patient’s symptom severity and motivation.

It is important to remember that either option is still just the beginning of the elimination diet process. Challenges or food trials, with foods the individual desires, can begin after four weeks and continue until the patient has a satisfactory range of foods to fit their lifestyle. It usually takes more than four months to develop a long-term individual diet.

Diet can also help with associated symptoms, such as reflux, which is helped by adjusting the volume, density and frequency of food intake. APDs consider management of stool consistency as well, with higher fibre and other foods that help with bowel motion softening in constipation, or lower grain fibre where looseness is present.

The fact that there is so much individual difference in foods tolerated continues to make this area of diet therapy one of the most challenging, so having an APD as part of the management team is essential.

An APD will guide patients through the process of working out which FODMAP compounds and food chemicals they might be reacting to and provide support for successful diet management long term. To find your local APD, search ‘Find an Accredited Practising Dietitian’ at or free call 1800 812 942.

Joan Breakey, B Sc. DNFS. Cert Diet. TTTC. M AppSc., Accredited Practising Dietitian Specialising in Food Sensitivity

Share this article:

Articles you might be interested in

Scroll To Top