Irritable Bowel Syndrome Nutrition Therapy

Picture of Written by Olivia Farrow, RD, MHSc

Written by Olivia Farrow, RD, MHSc

Reviewed by Krista Kolodziejzyk, RD, MPH, MBA

Irritable Bowel Syndrome Nutrition Therapy 

Want to learn more about irritable bowel syndrome nutrition therapy and how to support your clients with their nutrition goals? 

In this article, we share the importance of nutrition therapy in managing irritable bowel syndrome (IBS) and the must-know information on the low FODMAP diet.  

This article is based on DSC’s Irritable Bowel Syndrome, and low FODMAP courses for dietitians available in the DSC library. 


What is Irritable Bowel Syndrome (IBS)?

Irritable Bowel Syndrome (IBS) is a functional gut disorder, meaning there is nothing physically wrong with the gut but it’s not functioning the way it’s supposed to (1). The cause is unknown, but it is believed to be related to a few different factors, including (2,3)

  • Abdominal hypersensitivity – the gut is extra sensitive to reactions and sensations
  • Abnormal intestinal motility – the digestive system is moving too fast (diarrhea) or too slow (constipation)
  • Gut dysbiosis – an imbalance of the gut bacteria
  • Genetics
  • Psychosocial factors – including stress 


Why should dietitians know about IBS?

IBS is very common in Western countries, including the United States, United Kingdom and Canada, affecting approximately 11% of adults worldwide (4,5). 

Even though it’s not a life-threatening condition, it can be debilitating and have a large impact on the quality of life. Food plays a major role in digestion and dietitians are key for symptom management through nutrition. 


Symptoms of IBS

The symptoms you will see most commonly in IBS include (6):

  • Altered bowel movements (constipation, diarrhea, or both)
  • Gas production
  • Abdominal pain or discomfort
  • Bloating (the feeling of pressure in the abdomen, or distension)
  • Gastrointestinal (GI) distress related to psychosocial symptoms

Other symptoms might include (7,8)

  • Urgency
  • Depression or anxiety and stress
  • Fatigue and difficulty sleeping
  • Heartburn or reflux 


Red Flag Symptoms

IBS is commonly self-diagnosed, so it is important to ensure when working with a client that they have gone through adequate testing prior to diagnosis. Several conditions have symptoms that overlap with those of IBS, therefore testing can rule out conditions like GI cancer, celiac disease, or IBD (6,4). 

Some red flags that something more serious is going on include (4,6,9):

  • Family history of IBD, colon cancer, or other GI diseases
  • Anemia 
  • Hematochezia (blood in stool) or melena (black stool indicating upper GI bleeding)
  • Unintentional weight loss 
  • Older age at symptom onset 

Disordered eating behaviors and an unhealthy relationship with food are also red flags that a dietitian should look out for (10).


Irritable Bowel Syndrome Nutrition Therapy

Diet is very important in the management of IBS. Though there is no cure for IBS, symptoms can be managed, and quality of life can be improved with nutrition therapy. 

Keep in mind that IBS treatment is focused on finding a balance that works for that individual client. It’s about improving quality of life and having the least restrictive diet for the best symptom control for the client. Nutritional therapy for IBS should focus on ensuring adequate nutrition intake and managing symptoms where possible and desired by the client (6). 

IBS Nutrition Therapy  Options to Consider:

Fiber: With fiber, more is not always better, as it may trigger symptoms for some individuals (11). It is best to start with assessing current intake and symptoms. 


Hydration: If fiber intake is increased, fluid intake may also need to be increased, to support stool viscosity and transit (11). Individuals with diarrhea-related IBS should be assessed for risk of dehydration. 


Swallowing Air:

We all naturally swallow air once it gets into our system. Clients who have a lot of excess gas and bloating may benefit from swallowing less air. Recommendations you can give might include (11,12): 

  • Reducing carbonated beverages
  • Reducing chewing gum
  • Quitting or reducing smoking or tobacco product usage 
  • Eating more slowly 
  • Mindfully avoid talking while eating
  • Ensure proper fitting dentures 
  • Avoid the use of straws, and sipping hot beverages 


Regular Meals and Snacks:

Our bowels like routine and having regular, moderately sized meals and snacks spaced throughout the day can help with bowel regularity. Practices like a regular meal pattern, mindful eating habits, sitting down to eat, and thoroughly chewing food can improve symptoms of IBS (1113). 


Gut Stimulants:

Gut stimulants can make the bowels move faster, an issue with diarrhea-predominant IBS. Gut stimulants include caffeine, alcohol, and greasy or spicy foods (11,13). Sugar alcohols, often in sugar-free gums and candies can also contribute to diarrhea (14). 


Dietary Fat Consumption:

Individuals with IBS may avoid high-fat foods and meals due to symptoms of excess gas, bloating, and abdominal pain (13). There is limited evidence available on fat intake or fat restriction and IBS symptoms. These symptoms should be discussed with the client’s healthcare provider. 


Laxative Foods:

For constipation-predominant IBS some specific foods can help with constipation, including kiwi, flaxseeds, oatmeal, and prunes.


Food Triggers :

Most people with IBS report suspecting at least one food that seems to trigger their symptoms. But it can be tricky to figure out which foods are triggering these symptoms. A tool for determining food triggers include food and symptom diaries, available from DSC is the Food, Mood, and Symptom Diary Client Handout.

DSC’s Irritable Bowel Syndrome and FODMAP courses for dietitians, FODMAP dietitian resources, IBS dietitian resources including a food and symptom diary printable and digestive health dietitian resources can help you feel confident working with clients and their digestive health and IBS concerns. 


The Low FODMAP diet

The low FODMAP diet is an evidence-based elimination diet that dietitians and health professionals commonly use across the world for IBS symptom management. It can be challenging for a client to follow as it can take 8 to 14 weeks total to implement, and dietetic assistance is highly recommended. 

Unfortunately, with the growing popularity of the diet, many people try it by themselves with information from the internet, which can lead to nutritional deficiencies and other challenges. 

Read more about the FODMAP elimination diet and low FODMAP fiber sources here. 

Our IBS and Low FODMAP courses for dietitians and IBS FODMAP pdf printables can help you feel more confident supporting your clients with IBS nutrition therapy. 



Irritable bowel syndrome symptoms can greatly impact quality of life, but nutrition therapy can help with symptom management. Dietitians play a key role in IBS nutrition therapy and are essential in the process of a low FODMAP elimination diet. 

DSC’s IBS dietitian course includes a thorough overview of all of these supplements and a printable IBS FODMAP pdf supplement guide which includes info on digestive health supplements, their intended uses, doses, and side effects. 

Dietitian Success Center is THE professional development resource for dietitians and dietetic students. Our mission is to make it easier for dietitians and dietetic students to build expertise. We do this through evidence-based online nutrition courses, community, and ready-to-use client handouts. Plus – we give you the tools to start and grow your dietitian private practice! 

Disclaimer: the information provided in all written materials is for educational purposes only and is not to be used as medical advice or to diagnose or treat a medical disease. It is strictly for informational purposes and is general in nature. Dietitian Success Center Inc. is not responsible and cannot be held liable for any actions or inactions taken related to the information produced. Consult with your local medical provider before implementing any dietary changes. It is hereby understood that the information provided does not replace medical advice provided by your healthcare provider.



  1. Ford, Alexander C et al. “Irritable Bowel Syndrome.” The New England journal of medicine vol. 376,26 (2017): 2566-2578. doi:10.1056/NEJMra1607547
  2. Canadian Digestive Health Foundation. “Irritable Bowel Syndrome (IBS): Signs & Symptoms”. N.d., Available from 
  3. Chey, William D et al. “Irritable bowel syndrome: a clinical review.” JAMA vol. 313,9 (2015): 949-58. doi:10.1001/jama.2015.0954 
  4. Lacy, Brian E et al. “ACG Clinical Guideline: Management of Irritable Bowel Syndrome.” The American journal of gastroenterology vol. 116,1 (2021): 17-44. doi:10.14309/ajg.0000000000001036
  5. Canavan C, West J, Card T. The epidemiology of irritable bowel syndrome. Clin Epidemiol. 2014 Feb 4;6:71-80. doi: 10.2147/CLEP.S40245. PMID: 24523597; PMCID: PMC3921083.
  6. Raymond, J., Morrow, K. 2021. “Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders”. In Krause and Mahan’s Food & The Nutrition Care Process: 15th Edition. Pages 566-567. Elsevier, Inc. 
  7. Wang B, Duan R, Duan L. Prevalence of sleep disorder in irritable bowel syndrome: A systematic review with meta-analysis. Saudi J Gastroenterol. 2018 May-Jun;24(3):141-150. doi: 10.4103/sjg.SJG_603_17. PMID: 29652034; PMCID: PMC5985632.
  8. DeBortoli et al. “Overlap of Functional Heartburn and Gastroesophageal Reflux Disease with Irritable Bowel Syndrome.” World Journal of Gastroenterology 19, 35 (2013): 5787-97.
  9. Lacy, Brian E, and Nihal K Patel. “Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome.” Journal of clinical medicine vol. 6,11 99. 26 Oct. 2017, doi:10.3390/jcm6110099
  10. Kayar, Yusuf et al. “Eating disorders in patients with irritable bowel syndrome.” Gastroenterologia y hepatologia vol. 43,10 (2020): 607-613. doi:10.1016/j.gastrohep.2020.03.001 
  11. McKenzie, Y A et al. “British Dietetic Association systematic review and evidence-based practice guidelines for the dietary management of irritable bowel syndrome in adults (2016 update).” Journal of human nutrition and dietetics : the official journal of the British Dietetic Association vol. 29,5 (2016): 549-75. doi:10.1111/jhn.12385
  12. Nelms M, Sucher K, Lacey K. Nutrition Therapy and Pathophysiology: 3rd Edition. (2016). Cengage Learning 
  13. Cozma-Petruţ A, Loghin F, Miere D, Dumitraşcu DL. Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients! World J Gastroenterol. 2017 Jun 7;23(21):3771-3783. doi: 10.3748/wjg.v23.i21.3771. PMID: 28638217; PMCID: PMC5467063
  14. Grabitske, Hollie A, and Joanne L Slavin. “Gastrointestinal effects of low-digestible carbohydrates.” Critical reviews in food science and nutrition vol. 49,4 (2009): 327-60. doi:10.1080/10408390802067126 

Related Articles

Watch the Youtube video! Are you wanting to learn more about nutrition but don’t know where to start? In this...
Do you want to empower your clients to make lasting health changes and achieve their nutrition goals? Discover how motivational...
Watch the Youtube video here! Nutrition labels, and specifically the nutrition facts table, can help you compare packaged food and...
Whether you’re looking to start a dietitian side hustle, you want to leave your 9-5 job to pursue dietitian entrepreneurship full-time...
Quick Links Hey, Krista here! I am a fellow Registered Dietitian, dietitian business coach and the founder and CEO of Dietitian Success...
Watch the Youtube video here! Nutrition labels, and specifically, the Nutrition Facts Table, can help you compare packaged food and...