Low-FODMAP diet for IBS

Low-FODMAP diet: the evidence-based diet for IBS

The low-FODMAP diet was developed at Monash University in Australia and is now the first-line dietary therapy for irritable bowel syndrome (IBS). Up to 70-75 % of IBS patients experience significant symptom relief [1]. FODMAP stands for:

• Fermentable
• Oligosaccharides (fructans, GOS)
• Disaccharides (lactose)
• Monosaccharides (excess fructose)
• And
• Polyols (sorbitol, mannitol, xylitol)

These short-chain carbohydrates are poorly absorbed in the small bowel, draw water in, and are fermented in the colon → gas, bloating, pain and altered bowel habit.

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Three phases - all three are essential

Phase	Duration	Goal
1. Elimination	4-6 weeks	Remove all high-FODMAP foods → assess symptom response
2. Reintroduction	6-8 weeks	Reintroduce one FODMAP group at a time → identify triggers
3. Personalisation	Maintenance	Avoid only the triggers the patient reacts to long-term

Important: This is not a lifelong restrictive diet. Permanent low-FODMAP can damage the microbiome and cause nutritional deficiencies [2].

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High vs low FODMAP examples

Category	Avoid (high-FODMAP)	Allowed (low-FODMAP)
Fruit	Apples, pears, mango, watermelon, cherries	Banana (unripe), kiwi, strawberries, blueberries, orange
Vegetables	Onion, garlic, cauliflower, asparagus, peas	Carrot, cucumber, spinach, bell pepper, potato
Grains	Wheat bread, rye bread, pasta	Oats, rice, quinoa, gluten-free bread
Dairy	Milk, cream, soft cheese, yogurt	Lactose-free milk, hard cheese, lactose-free yogurt
Legumes	Lentils, chickpeas, kidney beans	Limited firm tofu
Sweet	Honey, agave, sorbitol/xylitol gum	Sugar, maple syrup, dark chocolate

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Evidence

• Halmos et al. (Gastroenterology 2014) - RCT showed >50 % symptom reduction on low-FODMAP vs typical Australian diet [1].
• Staudacher & Whelan (Gut 2017) - meta-analysis confirms effect in 50-80 % of IBS patients [3].
• Mansueto et al. (J Clin Gastroenterol 2015) - also effective in IBD patients with IBS-like symptoms.

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Who should NOT follow the diet uncritically?

• Patients with eating disorder history
• Malnourished or losing weight
• Children and pregnant women without dietitian supervision
• Patients without confirmed IBS - first exclude coeliac, IBD, BAM, SIBO

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Practical tips

• Use the Monash University FODMAP app - continually updated
• Dietitian supervision strongly recommended to avoid unnecessary restriction
• Read ingredient labels - onion/garlic powder is in many ready meals
• Personalisation is key - most people tolerate some FODMAPs in moderate amounts

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Treatment at Kirurgen.dk

We exclude organic causes (IBD, coeliac, BAM, SIBO) before dietary intervention - via colonoscopy, gastroscopy, blood tests and faecal calprotectin. See also: IBS, Bloating, SIBO, Gut microbiome, probiotics and IBS.

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References

1. Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology 2014;146(1):67-75.
2. Staudacher HM, Lomer MC, Farquharson FM, et al. A diet low in FODMAPs reduces symptoms in IBS and a probiotic restores Bifidobacterium species. Gastroenterology 2017;153(4):936-47.
3. Staudacher HM, Whelan K. The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut 2017;66(8):1517-27.