Irritable bowel syndrome (ÎÞÓǶÌÊÓÆµ) is a common gut disorder with symptoms like abdominal pain, cramping, bloating and changes in bowel habit. For some people this means constipation, for others diarrhea or even a combination of both. The symptoms of ÎÞÓǶÌÊÓÆµ can have a huge impact on quality of life for ÎÞÓǶÌÊÓÆµ patients.
Many people with ÎÞÓǶÌÊÓÆµ notice that what they eat seems to impact their symptoms. In fact, researchers have now even developed a specific ÎÞÓǶÌÊÓÆµ diet called the FODMAP diet. This is proven to help 75% of people with ÎÞÓǶÌÊÓÆµ better manage their symptoms. Aside from FODMAPs, other common ÎÞÓǶÌÊÓÆµ diet triggers that you may want to consider include dietary fiber, gluten, caffeine, fat, dairy (lactose) and alcohol.

Dietary fiber
Fibre is found in all plant-based foods such as fruits, vegetables, nuts and legumes/pulses. Fibre can be classified into many different types. Put most simply can be divided into insoluble fiber (does not dissolve in water) and soluble fiber (dissolves in water). Dietary fibre is not digestible is the body and plays a key role in bowel health.
Fiber adds bulk to stools (poo) and allows them to retain enough water to be soft and easy to pass. Not eating enough fibre, or having too much fiber can make ÎÞÓǶÌÊÓÆµ symptoms worse. It is recommended that adults eat 25-30g of dietary fiber every day, but most people don’t reach this daily target.
If you think fibre may be playing a role in your ÎÞÓǶÌÊÓÆµ symptoms, ´Ú¾±²ú°ù±ðÌý
supplements may also be useful. Talk to your doctor or ÎÞÓǶÌÊÓÆµ specialist dietitian for more advice.
Gluten-free diet
Gluten is a protein found in certain grains including wheat, rye and barley. For people with gluten causes inflammation and damage to the lining of their small intestine. Gluten containing foods (such as wheat bread and pasta) must be strictly avoided in the diet to prevent this damage.
In the past, some people with ÎÞÓǶÌÊÓÆµ, but not celiac disease, also found that their symptoms seemed to improve on a gluten free diet. This was often labelled a ‘gluten intolerance’. Clinical trials have since discovered the real reason people with ÎÞÓǶÌÊÓÆµ feel better and have less pain and bloating on a gluten free diet.
This is because gluten containing grains are also high in certain fermentable (gas producing) sugars known as fructans. Studies have now demonstrated that in the large majority of people with ÎÞÓǶÌÊÓÆµ, it is these . For this reason, a gluten free diet is not necessary for people with ÎÞÓǶÌÊÓÆµ.
Caffeine
Caffeine (usually in the form of coffee) is another commonly reported trigger of ÎÞÓǶÌÊÓÆµ with diarrhea. This may be because caffeine may have some kind of side effect of stimulating the bowel. Despite these reports, high quality studies have yet to show that reducing caffeine intake improves ÎÞÓǶÌÊÓÆµ symptom control.
Low-fat diet
Many people with ÎÞÓǶÌÊÓÆµ report that eating fatty foods such a deep-fried foods, pizza and ice cream seem to make their symptoms like diarrhea, gas and bloating worse. Including fattier, highly processed foods in the diet can also displace fresh, healthier alternatives like fruits, vegetables, wholegrains and low-fat dairy products. This may lead to a diet that is overall lower in fiber and also indirectly increase ÎÞÓǶÌÊÓÆµ symptoms.
A low-fat diet has not been specifically proven to improve ÎÞÓǶÌÊÓÆµ symptoms. However, avoiding eating large amounts of fried and highly processed fatty foods has many other health benefits.
Dairy-free diet
Some people with ÎÞÓǶÌÊÓÆµ report increased symptoms after eating dairy products. This can be due to a problem with digesting the sugar found in dairy products called lactose. When lactose is not digested in the small intestine, it is broken down by bacteria in the large intestine, usually causing diarrhoea, gas and bloating. This problem is known as lactose intolerance and seems to be more common in people with ÎÞÓǶÌÊÓÆµ with diarrhea.
Although lactose is found in large amounts in dairy products like milk and yoghurt, many cheeses are low in lactose because of processing and ageing. Lactose free versions of dairy milk and yoghurt are also now easily available for people with lactose intolerance, meaning that they do not need to follow a dairy free diet.
Alcohol
Alcohol is known to irritate the gut, and many people with ÎÞÓǶÌÊÓÆµ report that drinking alcohol can increase their symptoms. Some types of alcoholic drinks also contain FODMAP sugars, so may trigger ÎÞÓǶÌÊÓÆµ symptoms in this way. The NICE guidelines for ÎÞÓǶÌÊÓÆµ in the UK discuss considering your alcohol intake if excessive as part of an overall symptom management plan for ÎÞÓǶÌÊÓÆµ.
The FODMAP Diet
A low FODMAP diet is considered one of the best and most effective ÎÞÓǶÌÊÓÆµ treatments. Many studies and clinical practice have shown how effective the FODMAP diet is in providing relief from abdominal pain, constipation, diarrhea and bloating in up to 3 out of 4 people.
This diet does not ‘cure’ ÎÞÓǶÌÊÓÆµ, but does help a person with ÎÞÓǶÌÊÓÆµ work out the high-FODMAP foods that trigger their symptoms and how much of them can be tolerated. This is why a low FODMAP diet is not a diet for life, but helps a person learn which foods to eat without triggering symptoms.Â
The diet is a 3-step process designed to help you develop your best ÎÞÓǶÌÊÓÆµ diet.

Step 1 - Low FODMAP Diet
For 2-6 weeks - swap high FODMAP foods for low FODMAP foods.
Step 2 - Reintroduction Diet
Over 8-12 weeks FODMAP rich foods are reintroduced foods back into your diet one by one to identify which FODMAP types trigger your ÎÞÓǶÌÊÓÆµ symptoms, and which do not.
Step 3 - Personalization Diet
After identifying your high FODMAP trigger foods, foods that are well tolerated are reintroduced back into your diet. In the long-term it's about finding a balance between tolerated FODMAP-rich foods and the avoidance of others.
In most cases, people are able to reintroduce many high FODMAP foods back into their diet, but may not be able to eat them as often or in the same quantity as before.