This piece was written by one of our contributors; registered dietitian and health writer – Laura Tilt.
IBS is the most frequently diagnosed gut condition globally, affecting an estimated 1 in 10 people. So what causes it, and what are the routes to easing symptoms?
What exactly is IBS?
IBS (or irritable bowel syndrome) is a common condition which affects how the gut moves and functions, triggering symptoms like abdominal pain, bloating and a change in the frequency or appearance of your poo (stools).
It’s helpful to think of IBS as a condition where the gut has become extra sensitive, causing it to react differently to normal stimuli, like the movement of food, fluid and gas through the gut.
For years, IBS has been categorised as a ‘functional gut disorder’ – meaning that symptoms aren’t related to any disease or structural abnormalities. Instead, symptoms are related to a change in the way the gut functions – for example in its motility (movement) or sensitivity.
More recently, IBS has been renamed a ‘disorder of gut brain interaction’ (1), emphasising the influence of the gut brain axis (the communication that exists between the gut and the brain). For example, we know that stress can both trigger and exacerbate IBS symptoms. Studies also show that people with IBS are often affected by mental health conditions like depression and anxiety.
Who does IBS affect?
Statistics vary, but it’s estimated that IBS affects about 1 in 10 adults globally, usually those under the age of 50, and more commonly women than men. One possible reason for this is the influence of sex hormones on gut motility and sensitivity.
What causes IBS?
Research suggests there is no single cause of IBS, but a combination of factors which can overlap and play a role. These include genetics and environment in early life, life stressors, previous gut infections, alterations in gut motility (movement) or sensitivity, alterations in gut bacteria and disrupted communication between the brain and the gut (2). A specific subtype of IBS (known as post-infective IBS) is thought to develop in about 10% of people who have experienced gastroenteritis.
Can IBS be cured?
IBS is known as a chronic or long term condition, although symptoms tend to fluctuate over time. A review of studies which looked at how IBS progressed found that over a 2 year period
- 2-18% of people with IBS experienced a worsening of symptoms
- 30-50% found their symptoms were stable
- the remaining people experienced an improvement
One further study found that in people with post-infective IBS, about 30-40% experienced a resolution in their symptoms after 6 years (3).
How is IBS diagnosed?
There’s no test that can be used to diagnose IBS, so diagnosis is made on a symptom-based criteria. As part of the process, a doctor will check that there are no other possible causes for symptoms. This is necessary because the symptoms of IBS are very similar to those seen in conditions like coeliac disease and inflammatory bowel disease, so it’s important to get the correct diagnosis.
Further tests (like a colonoscopy or endoscopy, where a camera looks at your upper or lower gut), aren’t necessary to diagnose IBS, but your doctor might ask you to have these tests if they need more information, or suspect that there might be another cause for your symptoms.
I think I’ve got IBS but I’m not sure, what should I do?
If you’re experiencing persistent gut symptoms like tummy pain, bloating or a change in your poo that last longer than a couple of weeks, book an appointment with your doctor. They’ll ask you some questions about your symptoms and when they appeared, and will carry out a blood test (and possibly a stool test) to exclude other conditions.
IBS will be considered if you are experiencing ongoing abdominal pain at least one day a week which is associated with a change in your poo (what it looks like, or how frequently you go) or related to defecation (poo-ing). Other symptoms like bloating, wind or mucus in your stools are common but not necessary for a diagnosis.
I’ve been diagnosed with IBS, what are my options?
Broadly speaking there are three approaches to managing symptoms:
- dietary changes
- lifestyle changes
- and symptom-targeted medications.
You might find some or all of these help in easing symptoms.
Around 9 in 10 people with IBS feel that their symptoms worsen after meals (4), so dietary changes are often helpful. The following steps are are good starting point:
- try not to skip meals, make time to eat and avoid eating late at night
- limit alcohol to no more than two units per day (a 175ml glass of wine is 2.3 units) and aim for at least two drink free days a week
- reduce caffeine-containing drinks to no more than two mugs (three cups) a day
- reduce intake of fizzy drinks
- aim to drink least eight cups of fluid per day, especially water or other non-caffeinated drinks
- reduce rich or higher fat foods like chips, pies, batter, cheese, pizza, creamy sauces, snacks such as crisps, chocolate, cake and biscuits, spreads and cooking oils, and fatty meats such as burgers and sausages – in some people with IBS, fatty foods can trigger symptoms
- limit fresh fruit to three portions per day (one portion is 80g)
- Depending on your IBS subtype, adjusting your fibre intake can help too. If you have IBS-D (diarrhoea) you may benefit from reducing some types of fibre from whole-wheat breakfast cereals and breads, whereas if you experience IBS-C (constipation) you may benefit from eating more soluble fibre from foods like fruits, vegetables, oats and linseeds. You’ll find all these tips listed on the IBS food fact sheet from the British Dietetic Association.
Lifestyle changes involve our day-to-day habits including sleep, exercise, and relaxation time. Since stress is associated with a worsening of symptoms, tackling stress and how you relate to it can really make a difference. Try to create space for rest and relaxation each day even if it’s a bath or a cup of tea on a sunny step, and get yourself into a good routine sleep.
Many studies have found that yoga and mindfulness practices (typically when done regularly over a 8 or 12 week period) improve IBS symptoms (5,6). This might be because they help to reduce stress and anxiety or may regulate the gut brain axis.
Exercise can be helpful too – but bear in mind that high intensity exercise is often associated with more gut discomfort. Try to include gentle exercise like walking, swimming, cycling for 30 minutes a day.
Medications can be used to target specific symptoms such as cramps, diarrhoea or constipation. In some cases, a type of low-dose antidepressant may be beneficial in helping to manage abdominal pain. Speak with your doctor to explore options.
Can probiotics help?
Probiotics are live bacteria, which can benefit the health of the person taking them when consumed in sufficient quantities. There’s evidence that some people with IBS have changes in their gut microbiome which might contribute to symptoms, which is why there’s been interest in the use of probiotics.
However, evidence around probiotics improving IBS symptoms is inconsistent. In a recent review 7 of the research, experts looked at a range of good quality studies which had investigated the effects of probiotics in IBS over the last five years. Of 11 studies that investigated the effects of probiotics in IBS symptoms, (7) found there was a significant benefit in using a probiotic compared to a placebo (a ‘dummy’ treatment), whereas the remaining 4 found no difference in symptoms after supplementation.
Part of the challenge (and probably why we see such differences in results) is that different studies use different strains of probiotic bacteria, different combinations of strains and different doses. In the studies included in the review, 3 used a single strain probiotic (with just one type of bacteria) whereas the remaining 8 used a multi-strain probiotic. Overall, the beneficial effects were more notable in the multi- strain supplements which were supplemented over 8 weeks or more, but more evidence is needed to draw any conclusions.
If you want to try a probiotic, we usually recommend trialling a product for 4-8 weeks and to keep a symptom diary to see if you notice a benefit. If not, try a different brand or strain.
What about the low FODMAP diet?
If you’ve tried dietary and lifestyle changes and they’ve not helped, you can consider a trial of the low FODMAP diet. This is a type of elimination diet which was developed by scientists at Monash University in Australia to help improve IBS symptoms.
Put simply, FODMAPs are a group of short-chain carbohydrates (sugars) that are poorly absorbed in the gut, which can trigger symptoms like pain, wind, bloating and loose stools in people with IBS.
FODMAPs are found naturally in a range of foods including onion, garlic and wheat, and there’s nothing ‘unhealthy’ about them – in many cases they’re found in healthy foods like fruits and vegetables. What differs between people with and without IBS is the potential of these sugars to cause gut discomfort.
In people without IBS, FODMAPs move through the bowel without much consequence. But, in people with IBS, they can trigger symptoms such as abdominal pain, bloating, wind and loose stools, because they are poorly absorbed and readily fermented by gut bacteria. The bacteria turn the sugars into gas, which can result in bloating and pain.
It is important to note that the low FODMAP diet is not a long term diet – the elimination phase (where you reduce FODMAPs) only lasts for a maximum of 2-6 weeks. If during this time you experience an improvement in symptoms, you’ll move onto a reintroduction period where you re-introduce various high FODMAP foods systematically, to determine what FODMAPs you can tolerate and in what portion sizes. Longer term, you’ll only limit those you’re sensitive to, with the aim of returning to as minimally restrictive a diet as possible.
Studies show the low FODMAP diet provides symptom relief in about 70% of people with IBS when delivered by a FODMAP trained dietitian (8). It’s important to note that this diet should only be followed with the help of a FODMAP trained dietitian, as the diet is both restrictive and challenging to follow. You can ask for a referral to a dietitian from your G.P., alternatively you can look for a FODMAP trained dietitian working privately through the freelance dietitians directory – use FODMAP in the search box.
When dietary changes aren’t suitable
It’s important to be aware that dietary changes aren’t always the right approach, especially if you already have a restricted diet, or a history of disordered eating. Studies show that a large percentage of patients with an eating disorder meet the criteria for IBS, and in these cases further dietary restriction is not recommended. If you are affected by disordered eating, it’s important to get help from a specialist and to work on restoring energy availability.
Gut focused psychotherapy
Lastly, I want to mention two forms of gut-focused psychotherapy which are delivering promising results for symptom management.
Gut directed cognitive behavioural therapy (CBT) looks at how thoughts and emotions can impact physical sensations like abdominal pain. Over a number of sessions, a therapist will work with an individual to determine how stress and emotions are related to their IBS symptoms, and to establish and practice tools that can help manage stressors. This service is available through the NHS, but there is a digital option too – Zemedy is a science backed, CBT-based app for people with IBS, which was shown to have a positive impact on symptoms and quality of life in a recent clinical trial (9).
The second approach is gut directed hypnotherapy, a form of hypnotherapy which addresses disrupted miscommunication between the brain and gut. First described in 1984, the therapy involves muscular and mental relaxation alongside suggestions to normalise gut function, delivered over a series of sessions with a specially-trained hypnotherapist. Studies have found gut directed hypnotherapy to be an effective way of reducing IBS symptoms in people who have tried other strategies without success (10).
More recently, researchers compared the effects of a low FODMAP diet with gut directed hypnotherapy in a group of people with IBS, finding that both approaches were equally successful at relieving symptoms 11 . This is a really positive finding that highlights the potential of therapies targeting the gut- brain axis for reducing symptoms, without the need for dietary restriction.
If you’re thinking of working with a hypnotherapist for IBS, check they are specifically trained in this form of hypnotherapy and registered with the National Council for Hypnotherapy. Alternatively, check out Nerva, which is a science backed self guided programme of gut directed hypnotherapy.
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