Inflammatory bowel disease (IBD) includes Crohn’s disease and ulcerative colitis and is an auto-inflammatory condition of the gastrointestinal tract. IBD is mostly managed with medications, which aim to treat the inflammation (i.e., heal the gut). However, symptoms commonly seen in people with IBD, including abdominal pain, diarrhoea, bloating and constipation, may not always indicate inflammation. People with IBD are three times more likely than the general population to have irritable bowel syndrome (IBS), which refers to a condition affecting the ‘function’ of the bowel and involves an increase in bowel sensitivity rather than inflammation of the bowel. If you have IBD, it is important to ensure that the presence and degree of inflammation is not based only on symptoms. Your doctor will interpret various tests and guide you as to whether your symptoms are inflammatory (active IBD) or functional (IBS) or both.
Key thing to know about diet in IBD:
- Studies are underway to investigate whether diet can be used to treat gut inflammation in IBD, however there is currently not enough evidence to recommend any particular diet as effective.
- Studies show that a low FODMAP diet will help to treat up to three-quarters of people with IBS and there is evidence to show that a low FODMAP diet also helps control symptoms in the majority of people with both quiescent (inactive) IBD and IBS.
- FODMAPs act as prebiotics in the gut, meaning they stimulate the growth of good bacteria, which is probably important if you have IBD, so always aim to minimise your FODMAP restriction. A dietitian can guide you on how to find the level of FODMAP restriction suitable for you.
- A gluten free diet will only heal the gut in people with coeliac disease, not IBD. However, many people with IBD feel better on a low gluten or gluten free diets to treat their IBS. Gluten and FODMAPs are found in the same grains, so people may feel better because FODMAPs are incidentally reduced on a gluten free diet.
- Low fibre and low residue diets are only recommended in special circumstances, e.g., if you are at risk of bowel obstruction (blockage). Your doctor and dietitian will tell you if this type of diet is indicated.
- People with IBD may have increased requirements of certain nutrients, so it is important that you do not restrict your diet without advice from a dietitian.
- Pedersen N, Ankersen DV, Felding M, et al. Low-FODMAP diet reduces irritable bowel symptoms in patients with inflammatory bowel disease. World Journal of Gastroenterology. 2017;23(18):3356-3366. doi:10.3748/wjg.v23.i18.3356.
- Prince AC et al (2016) Fermentable Carbohydrate Restriction (Low FODMAP Diet) in Clinical Practice Improves Functional Gastrointestinal Symptoms in Patients with Inflammatory Bowel Disease. Inflamm Bowel Dis 22(5):1129-36.
- Gearry RB et al (2009) Reduction of dietary poorly absorbed short-chain carbohydrates (FODMAPs) improves abdominal symptoms in patients with inflammatory bowel disease – a pilot study. J Crohns Colitis 3(1):8-14.
- Halmos EP et al (2016) Consistent Prebiotic effect on Gut Microbiota with Altered FODMAP Intake in Patients with Crohn’s Disease: A Randomised, Controlled Cross-Over Trial of Well-Defined Diets. Clin Tranls Gastroenterol 14(7):e164.