How IBS and diet are linked  

IBS (Irritable Bowel Syndrome) is one of the most common digestive conditions, affecting one in ten of us worldwide.

It is an ongoing condition affecting the stomach and intestines, also known as the gastrointestinal tract.

Symptoms include tummy pain, diarrhoea, constipation, and bloating.  

Though the causes of IBS are unknown, diet plays a key role in triggering IBS symptoms with 70-89% of people with IBS report that foods trigger their symptoms. 

Read our guide to IBS. 

Why do foods trigger IBS? 

Certain foods and drinks are known to cause an unbalance in the gut microbiome through fermentation. Known as dysbiosis, this change in the gut has been linked to IBS symptoms. Dysbiosis can also be caused by stress, anxiety, medication, infections, vitamin D deficiency and genetics.

Food can also directly stimulate nerves in a sensitive digestive tract and cause a variety of reactions.

FODMAPs: common IBS diet triggers 

Everyone is different, however there are certain foods and drinks that often trigger IBS flare-ups. 

Most of these foods fit into the category of ‘FODMAPs’, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. 

FODMAPs are short chain carbohydrates that may be absorbed poorly by the large bowel, drawing fluid into the bowel leading to diarrhoea, and fermenting which causes excess gas. 

These include:  

Milk and dairy products

Many people suffer from lactose intolerance, where the body doesn’t have the enzymes to break down certain sugars in dairy. Instead, the body disposes of these sugars very quickly, often in the form of diarrhoea.

Vegetables

Vegetables such as cauliflower, brussels sprouts, garlic and  onions are difficult to digest and can cause excess wind. 

Fructose 

Fruit, fruit juices, soft drinks, sweets and preservatives are high in fructose (fruit sugar). If you are sensitive to fructose, this can lead to extreme wind and diarrhoea.

Sweeteners  

Some people are sensitive to sweeteners, particularly those ending in ‘OL’, such as sorbitol or xylitol. These are sugar alcohol sweeteners which ferment in the gut and can cause diarrhoea.  

Other parts of your diet that may trigger IBS symptoms 

Rich or fatty foods

It is very common to get loose stools following unusually rich or fatty meals, particularly if you don’t usually eat them.

Caffeine 

Stimulants like caffeine can affect bowel movements and increase the likelihood of IBS symptoms; high alcohol intakes can affect digestion and cause loose stools. 

High fibre foods

A diet rich in high fibre foods such as fruit, vegetables, beans, wholegrain bread, wholegrain rice, nuts and seeds can cause diarrhoea.

Fizzy drinks

Fizzy drinks contain gas which may contribute to wind and bloating. 

Food to eat to prevent symptoms

While certain foods trigger IBS symptoms, other foods can help improve your symptoms whilst nourishing your microbiome and reducing dysbiosis: 

• Probiotic live strains of bacteria suitable for IBS can be trialled for 1 month. These will only work for as long as they are consumed and if they help, continue use. Live bacteria found in yoghurts and some drinks may also add moisture content to the large bowel and rebalance the gut microbiome – read our guide to probiotics and IBS.   what guide?
• A low FODMAP diet can be trialled particularly in diarrhoea predominant symptoms.
• Try eating more fibre or linseeds and upping fluid if you have constipation.*  Sometimes a low FODMAP diet can also help particularly if bloating and wind are effecting you. 
• Green tea polyphenols and supplements containing curcumin and vitamin D also feed gut bacteria.  
• Drink plenty of fluids to help the fibre move through your bowel – at least 8-12 cups per day is recommended depending on your weight, the heavier you are, the more you need.  

How to identify what foods in your diet are causing IBS symptoms

Foods that cause symptoms are all very individual and therefore it is important you find out what your own trigger foods are.

It may be tempting to cut out foods without the bother of professional help. However, limiting too many foods can cause an unbalanced diet in terms of fruit, veg, carbs, fats and proteins, or even micronutrient deficiencies. 

Furthermore, cutting out too much can also worsen IBS symptoms! By restricting you diet you can end up cutting out the foods that your gut bacteria need to thrive.

Instead, you can identify your “triggers” by taking these steps: 

Talk to the experts

It is key to work with a dietitian experienced in gut health who can help to identify a suitable diet, such as a low FODMAPs diet,  and help you reintroduce foods.

You can get advice in a free 15 minute support call with one of our expert nutritionists who specialises in IBS symptoms.

Test one food at a time

If you think that a certain food causes IBS symptoms, then eliminate it for a few weeks and then reintroduce it in small amounts. 

Keep an IBS diet diary 

This will  help you to monitor the effect different foods have on your IBS symptoms. You can then show it to any professionals you see too.

Seek medical advice 

It is important to have a diagnosis of IBS confirmed so that other gut health conditions such as SIBO, coeliac disease and Inflammatory Bowel Disease (IBD) can be ruled out. 

Visiting a GP is a good start and they may refer you on to a gastroenterologist to have a look inside the gut.  

Other ways to manage IBS symptoms 

Along with changing the foods you eat, there are other dietary changes you can make to help manage your IBS symptoms:

Take probiotic and natural food supplements

• Many people now try natural food supplements which calm inflammation and treat deficiencies.
• There are probiotic supplements which aim to treat the gut microbiome imbalance directly
• Green tea polyphenols and supplements containing curcumin and vitamin D also feed gut bacteria.  

Read our guide to IBS supplements.

Aim for regular, healthy, balanced meals 

• Don’t leave more than four hours between meals as it may increase wind. 
• Try to cook from scratch, and keep the portion size moderate.
• Your lunch should be your main meal of the day and go lighter in the evening. 

Take your time when eating

• Eat in a calm environment, chewing your food well. 
• Playing classical or spa music during meal times is a good idea, taste your food and eat slowly, as your saliva is the start of the digestion process, which gives your gut less work further down the line.

Look after your mental health 

• It is important to manage your mental health before you change your diet. 
• Stress is a major cause of IBS symptoms, so if stress is your trigger, there’s no point changing your diet first.
• Relaxation therapies, exercise routines and behaviour management are vital. Even 10 minutes of daily mindfulness can reduce gut-disrupting stress hormones.

Banish gut health issues with the Gut Health Protocol

• Our Gut Health Protocol is a two-part approach designed to fortify your digestive system and deliver real results. 

Frequently Asked Questions about an IBS-friendly diet

What is a low FODMAP diet and how does it help IBS?

FODMAP stands Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols: short chain carbohydrates that may be absorbed poorly by the large bowel, drawing fluid into the bowel leading to diarrhoea, and fermenting which causes excess gas. 

Many people with IBS follow a low FODMAP diet to help manage symptoms, though supplements may be required to fill in any deficiencies in vitamins and minerals – read our guide to IBS supplements.