Dietary triggers are common, with up to nine out of 10 individuals reporting that food generates symptoms. Two-thirds of individuals with IBS initiate dietary restrictions to improve symptoms, therefore dietary management is an important option within medical treatment.

For many people IBS will often come and go throughout their life, with up-to 75% of people continuing to suffer from symptoms 5 years after being diagnosed.
The exact cause of IBS is unknown as it is a complex interplay of many contributory factors such as stress, diet, gastroenteritis and prolonged antibiotic use, surgery, gut bacteria and low grade inflammation. Although there is no known cure the symptoms can often be managed through diet, exercise and lifestyle interventions.

The symptoms of IBS can vary person to person and are highly individualized. The most common symptoms can include:
• Gas / Wind
• Bloating
• Motility
• Pain or discomfort in the abdomen
• Sensitive or inflamed gut
• A combination of the above

Practical Considerations
If you suffer from IBS you should be seeking out the correct advice. Unfortunately, it is known that most people suffering with IBS don’t seek medical advice and would rather rely on self-care.
Due to the wealth of new research the British Dietetic Association (BDA) systematically reviewed all the evidence for the role that diet plays in the management of IBS and updated its guidelines.

Here are the latest guidelines worth considering:

• Look at your alcohol intake in relation to your symptoms to determine whether a reduction may help relieve symptoms.
• If caffeine appears to be related to your symptoms, consider reducing intake. Daily caffeine intakes up to 400mg/day do not raise any safety concerns in the general population, apart from in pregnancy where 200mg/day is the current maximum.
• A decrease in fat intake may be beneficial in relieving IBS symptoms, in particular meal related abdominal pain and discomfort associated with visceral hypersensitivity (pain within the inner organs).
• Despite the lack of evidence, a gradual increase in fluid intake is recommended to improve stool frequency and decrease the need for laxatives in IBS-C. Aim for a total intake of 1.5-3.0L/day.
• Again, despite the lack of evidence, aiming to achieve a healthy balanced diet with a regular meal pattern of breakfast, lunch, and an evening meal with snacks as appropriate is recommended. With focus placed on taking your time over meals, sitting down to eat, chewing food thoroughly and not eating late at night. Although this will be tricky if on shift work.
• Lactose restriction may only provide marginal symptom benefits. It is generally only considered as part of a low FODMAP diet. If you wish to follow a milk-free diet, take note that there is no high-quality evidence for this to improve IBS symptoms.
• Evidence is also lacking on whether the recommended 25-30g/day dietary fibre intake for the general population is applicable if you suffer with IBS. It’s important to look at your symptoms to determine whether your current intake of dietary fibre is optimal. Looking at the fibre intake from all potential sources i.e cereals, grains, fruit, vegetables, nuts, seeds, pulses and mycoprotein is recommended, and if an increase is applicable, it’s encouraged to look at the consumption from a wide variety of high fibre starchy foods such as oats and oat bran, brown rice, rice bran, wholemeal/seeded/granary bread, whole-grain pasta, whole-grain couscous, rye-based bread, potatoes with skin, and quinoa. The importance of looking at a wide variety of dietary fibre intake will help taking into account any other dietary restrictions, obviously symptom allowing.

Linseeds are a useful source of dietary fibre providing 22.8g of dietary fibre per 100g of whole seeds. It’s recommended to start with 4-12g/day of linseeds and increase up to 24g/day. Linseeds can also be added to other foods such as yoghurt, breakfast cereal, porridge, homemade bread, casserole, soup, and salad. It also doesn’t matter whether linseeds are golden or brown, whole or ground. But always ensure they are consumed with fluid (150mL). 

• A low FODMAP diet with a food restriction phase for 3-6 weeks is efficacious in the treatment of IBS, but this must be delivered by a dietitian with expertise in FODMAP education.
Evidence shows that in the short-term a low FODMAP diet alters the microbiota in the gut. Therefore, if symptoms show signs of improvement during 3-6 weeks, the reintroduction of individual FODMAPs to personal tolerance levels is necessary, providing that the recommendations are delivered by a dietician with expertise in the area. The goal is always to enable long-term self-management.
• If you wish to follow a gluten-free diet, take note that the current evidence for its use is conflicting. The long-term effects of a gluten-free diet in IBS are unknown. In coeliac disease, a gluten-free diet is used as a life-long treatment and can impair quality of life.
• If you choose to try probiotics you should be aware that some products contain other ingredients that may increase IBS symptoms i.e. dietary fibre, oats, FODMAPs, inulin, lactose, fructose, sorbitol and xylitol. If you do try probiotics and find that after 4 weeks of use it is of benefit, you can continue to take them but the long-term effects are not known.
• The only focused elimination-type diet that is appropriate for IBS is the low FODMAP diet. No other elimination diets have mechanistic evidence or clinical evidence to defend their use.

The basic first-line of advice in dealing with symptoms of IBS is to consider ‘healthy eating and your current lifestyle’, looking at the intakes of alcohol, fat, fibre (depending on symptoms), milk, spicy foods and use of probiotics. You should also be aiming to reduce your stress levels and exercise more. The aim is to treat the symptoms not IBS.

IBS-D = Reduce soluble fibre i.e wholegrain bread, bran, cereals, nuts, seeds (not linseeds).
IBS-C = Increase soluble fibre i.e oats, barley, rye, fruit, root vegetables, linseeds.

The second-line of advice that should be considered when IBS symptoms persist after looking at your health and lifestyle, is that of a low FODMAP diet delivered by a dietitian with expertise in the area.

So there you have it. As you can tell Irritable Bowel Syndrome is a somewhat complicated, highly individualistic disorder that affects so many of us in entirely different ways. A protocol which may help one person with their symptoms will not necessarily help someone else with their own. So it’s vitally important that you treat your own individual symptoms according to the guidelines.

A few other things to take note of is that there is a lack of evidence to recommend a gluten-free diet or any non-specific food hypersensitivity interventions for treating IBS, and if your symptoms include constipation, following a low FODMAP diet is not recommended.