Dietary Approaches for IBS: What Works?

Irritable bowel syndrome (IBS) affects four in ten people. This common gut disorder has a substantial impact on quality of life and is also associated with a high economic burden, both in terms of direct costs for the healthcare system and loss of productivity. People with IBS prefer diet as a first-line approach, explained by the fact that food can trigger a worsening of symptoms and diet is often associated with fewer side effects than medications¹.

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There are different science-based dietary options worth considering for managing IBS, including whole diets, foods and drinks, and supplements².

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Whole diets for IBS

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A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is the most researched diet in IBS. FODMAPs are a group of short-chain carbohydrates that resist digestion in the small intestine and enter the colon intact, where they attract water and are fermented by the gut microbiota.

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However, a low-FODMAP diet is costly and time-consuming, it’s restrictive, and requires carefully reintroducing foods to identify the ones that aren’t tolerated. As a result, it may not be appropriate for those who have or are at risk of developing an eating disorder.

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That’s why simpler dietary tweaks are encouraged as a first-line dietary approach in IBS:

• Eating more slowly
• Having regular, smaller, and more frequent meals
• Limiting foods that could trigger symptoms (e.g., coffee, tea, carbonated beverages, alcohol, and fatty or spicy foods)

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Another whole diet worth adding to the menu of evidence-based diets for IBS is the Mediterranean diet. Emerging evidence suggests the potential benefits of the Mediterranean diet in people with diarrhea-predominant IBS^3,4, particularly in those with anxiety⁵.

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While some people with IBS think they are sensitive to gluten or wheat, the reality is that they may not actually react to these ingredients. Fructans, a type of fermentable carbohydrate found in wheat, onion, and garlic, and negative expectations and beliefs, rather than gluten, may be driving symptoms in many cases. The best way to differentiate gluten sensitivity from fructan intolerance involves first ruling out celiac disease and then using short-term dietary trials and re-introduction with dietitian support to identify personal triggers safely⁶.

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Foods for IBS

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While there is no “magic” food that cures IBS, a few human trials have shown that changes in the quantity or type of one or two foods could ease IBS symptoms. For instance, kiwifruits, prunes, and rye bread could regulate bowel habits through their fiber content and modulation of the gut microbiota⁷.

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There are also high-fiber foods low in FODMAPs (e.g., chia seeds, oat bran, oatmeal, rice bran, quinoa, white potato with skin, kiwis, oranges, or tangerines, to name a few) worth trying as a first-line approach before moving to more restrictive diets.

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It’s important to increase slowly with adequate water to allow the colonic environment to adapt to the diet change and first discuss your fiber goals with a dietitian or doctor. The ultimate goal is to eat the most variety of fiber-rich foods as possible, within personal tolerance.

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Supplements and nutraceuticals for IBS

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When it comes to fiber advice in IBS, it’s important to shift the focus from the advice of “avoid fiber” to “eat the right type of fibers”. Psyllium (ispaghula husk) is one of the most researched fibers in IBS. It’s a viscous and partially fermentable fiber worth considering for some patients with diarrhea or constipation-predominant IBS, while wheat bran can worsen IBS symptoms. A good idea is to start with low doses of psyllium, adding about 2-3 grams every 2 weeks to test tolerance and increase up to 10 grams daily².

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Some nutraceuticals for IBS supported by at least one clinical trial are⁷:

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• Peppermint oil: it’s a natural antispasmodic that acts by relaxing the smooth muscles of the gastrointestinal tract.

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• Palmitoylethanolamide (an endogenously-produced lipid-like molecule similar to endocannabinoids and with anti-inflammatory properties) and polydatin (a precursor of resveratrol): could improve IBS remission rates.

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• Some probiotics and postbiotics could benefit some patients with IBS by boosting beneficial gut bacteria, reducing pathogens, and strengthening gut barrier function. However, the role of prebiotics in IBS is controversial, as when administered at high doses can worsen flatulence and abdominal pain.

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• Glutamine: maintains proper gut barrier function and could help patients with diarrhea-predominant IBS and increased intestinal permeability.

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If you’re a patient with IBS, work with your healthcare provider to individualize the right nutraceutical based on your medical history and symptoms.

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What’s the bottom line?

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• While traditional dietary advice for IBS has focused on what to exclude, emerging research suggests that diets that include foods known to be important for gut and overall health could improve both psychological and gut symptoms in people with IBS.

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• Not all dietary fibers work equally in IBS. Instead of following a low fiber diet, it’s better to focus on choosing the right fiber (preferably in the form of food).

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• Some nutraceuticals for IBS supported by scientific evidence include peppermint oil, palmitoylethanolamide, some probiotics and postbiotics, and glutamine.

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References:

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1. Sturkenboom R, Keszthelyi D, Masclee AAM, et al. Discrete choice experiment reveals strong preference for dietary treatment among patients with irritable bowel syndrome. Clin Gastroenterol Hepatol. 2022; 20(11):2628-2637. doi: 10.1016/j.cgh.2022.02.016.
2. Whelan K, Ford AC, Burton-Murray H, et al. Dietary management of irritable bowel syndrome: considerations, challenges, and solutions. Lancet Gastroenterol Hepatol. 2024; 9(12):1147-1161. doi: 10.1016/S2468-1253(24)00238-3.
3. Singh P, Dean G, Iram S, et al. Efficacy of Mediterranean diet vs. low-FODMAP diet in patients with nonconstipated irritable bowel syndrome: a pilot randomized controlled trial. Neurogastroenterol Motil. 2025; 37(10):e70060. doi: 10.1111/nmo.70060.
4. Bamidele JO, Brownlow GM, Flack RM, et al. The Mediterranean diet for irritable bowel syndrome: a randomized clinical trial. Ann Intern Med. 2025; 178(12):1709-1717. doi: 10.7326/ANNALS-25-01519.
5. Staudacher HM, Mahoney S, Canale K, et al. Clinical trial: A Mediterranean diet is feasible and improves gastrointestinal and psychological symptoms in irritable bowel syndrome. Aliment Pharmacol Ther. 2024; 59(4):492-503. doi: 10.1111/apt.17791.
6. Biesiekierski JR, Jonkers D, Ciacci C, et al. Non-coeliac gluten sensitivity. Lancet. 2025; 406(10518):2494-2508. doi: 10.1016/S0140-6736(25)01533-8.
7. Marasco G, Cremon C, Salvi D, et al. Functional foods and nutraceuticals in irritable bowel syndrome. J Clin Med. 2025; 14(6):1830. doi: 10.3390/jcm14061830.

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