Irritable Bowel Syndrome and the low FODMAP diet
Written by MVMs on site dietician Penny Oxby APD. For advice on following a low FODMAP diet, please book an appointment with Penny. If you are wondering if you might have IBS, please book an appointment with one of our doctors.
Do have gut symptoms that come and go such as abdominal pain, excessive gas, bloating and alternating bowel habits (diarrhoea, constipation or both)? Like 1 in 7 Australian adults, you might have irritable bowel syndrome (IBS). The cause of IBS is unclear but is likely to be due to many factors such as gut sensitivity, accelerated or delayed gut transit time, low grade inflammation or altered gut microbiome. Although there is no cure for IBS, there are a range of therapeutic strategies available to manage your symptoms. At Milton Village Medical, our dietitian can guide you through the low FODMAP diet to help decode your food sensitives for improved symptom management.
IBS is known as a functional gut disorder, which means that the gut is otherwise normal except for its function (the way it feels and responds to stimuli leading to symptoms). It’s is also true that there are many factors that contribute to IBS-like symptoms, which include:
• diet (fat, fibre, alcohol, caffeine and food intolerances such as FODMAPs or food chemicals)
• altered pelvic muscle function (incontinence, slow transit constipation)
• the gut-brain axis (anxiety and stress)
• meal size and eating pattern (overloading stretch receptors).
If you think you may have IBS, it’s important for you to discuss your bowel symptoms with your doctor. Your doctor may arrange further investigations if appropriate (typically a blood test and stool sample), to exclude other potential causes of your symptoms. IBS diagnosis is made on symptoms (there is no test) using the Rome IV criteria for IBS.
What are FODMAPs?
“FODMAP” is an abbreviation for a group of short-chain carbohydrates found naturally in a variety of fruit, vegetables, grains, legumes and dairy.
digested by gut microorganisms producing gas
Chains of sugar molecules such as fructans and galacto-oligosaccharides (GOS) found in onion, garlic, wheat, barley, rye, inulin, some dried fruit and legumes
Two sugar molecules making lactose found in milk, yoghurt, some soft cheeses, ice cream, custard and cream
One sugar molecule; fructose in excess of glucose
Sugar alcohols such as sorbitol, mannitol, maltitol, xylitol and isomalt found in cauliflower, mushrooms, stone fruit and “sugar free” products like mints and gum.
Some FODMAPs are poorly absorbed by everyone (e.g. fructans and galacto-oligosaccharides or GOS). In people with IBS, problems with gut sensitivity and gut motility can result in exaggerated responses to high FODMAP foods. High FODMAP foods draw water into the gut and produce excess gas in the large intestine. This can cause distention (‘stretching’ of the abdominal wall), bloating (from excess wind) and abdominal pain.
Although FODMAPs do not cause IBS, a well-planned low FODMAP diet can reduce IBS symptoms. Remember, if you think you may have IBS, it’s important to discuss your symptoms with your doctor before making changes to your diet.
What is a low FODMAP diet?
A low FODMAP diet is a short-term diet used in the first phase of your nutrition therapy with your dietitian. This diet is usually recommended for 2-6 weeks at a time. Progress should be monitored by your dietitian to ensure that your diet is nutritionally adequate, and not overly restrictive. Your dietitian will also guide you through FODMAP re-challenges if you experienced symptom improvement on a low FODMAP diet. The overall goal is to achieve better symptom management while enjoying the greatest dietary variety possible for optimal gut health and well-being.