IBS and Fiber

Irritable Bowel Syndrome (IBS) is one of the most common referrals to gastroenterologists with a prevalence of 4.4 - 4.8% in the United States, United Kingdom and Canada. Direct medical costs attributed to IBS in the United States, excluding prescription and over-the-counter medications are estimated to be as high as $1.5 - $10 billion per year. (1) Many physicians believe that IBS is due to insufficient fiber intake and will recommend an increase in dietary fiber. (2) Many research studies are reporting limited improvement in symptoms and are now looking towards fiber types as better recommendation to reduce symptoms.

Guiding Question: Does fiber help or hurt patients with IBS?

Audience: Healthcare Professionals Including RD/N, LPN, RN, NP, MD

Learning Objectives:

• Review the definition and pathophysiology of IBS
• Review diagnostic criteria for IBS
• Review types of IBS
• Review diet management
• Review fiber's role in diet
• Review recommended clinical guidelines for IBS management

What is IBS? What are the symptoms?

https://youtu.be/HOq4GwPB8Mk

https://youtu.be/z9SZK47jPPI

 Review:

• IBS is a set of symptoms which include abdominal pain/cramping, abnormal bowel habits (diarrhea, constipation or mix), bloating, distension and flatulence.
• Highly common GI disorder affecting ~10 - 20% adults worldwide
• More common in females than men
• Often diagnosed in younger age
• Symptoms often worsen after eating a meal
• Greatly impacts quality of life
• Involves disturbances in brain-gut axis
  • 95% of serotonin is found in the GI tract
  • People with IBS have a dysfunctional serotonin-mediated mechanism that alters intestinal barrier functions
• Many patients confuse food allergies / lactose intolerance with IBS

What causes IBS?

https://youtu.be/PmTgdReJpbY

How is IBS diagnosed?

https://youtu.be/Fvu9cnsksQA

• Rome IV criteria What is the Rome IV criteria?      Rome IV Criteria - Rome Foundation
  • Abdominal pain on average at least 1 day / week in last 3 months associated with 2 or more of:
    • Onset of pain associated with a change in frequency and appearance of stool
    • Abnormal stool form
    • Defecation straining / urgency
    • Passing mucus
    • Feeling of incomplete emptying

What are the different types of IBS?

• IBS-D: Diarrhea
• IBS-C: Constipation
• IBS-M: Mixed
• IBS: unclassified

Managing and treating IBS:

https://youtu.be/hgWYQG6MnGY

IBS and diet:

• Widely believed that IBS is caused by fiber intake deficiency
• Common recommendation is to increase fiber intakes and decrease gas-producing foods (i.e. beans, broccoli, cauliflower, cabbage, bananas)
• Research studies showing that increasing fiber did not improve IBS symptoms; focus more on type of fiber
• Trial of temporary diet plan of low FODMAP (Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, Polyols) until IBS symptoms improve
• Elimination diet with gradual reintroduction (cow's milk, wheat, soy, corn, yeast, refined sugar, eggs)

What is the role of fiber in diet management for IBS?

https://youtu.be/edkeEFEv5t0?si=I-QDNUe1IgdVB1PY

Pertinent Reference Articles:

• Diet in irritable bowel syndrome - PMC
• Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial - PMC

What is the American College of Gastroenterology recommended clinical guidelines for managing IBS?

ACG_Clinical_Guideline__Management_of_Irritable.11.pdf

• American College of Gastroenterology (ACG) recommended guidelines for the management of irritable bowel syndrome (2):
  • Recommend serologic testing to rule out Celiac disease (moderate quality of evidence)
  • Recommend categorize patients based on IBS subtypes
  • Recommend trial of low FODMAP diet (very low quality of evidence)
  • Recommend soluble vs. insoluble fiber to treat symptoms (moderate quality of evidence)
  • Do not recommend testing for food allergies unless reproducible symptoms
  • Do not recommend probiotics for treatment of symptoms (very low quality of evidence)
  • Do not recommend PEG products to relieve IBS symptoms (low quality of evidence)
  • Do not recommend fecal transplant for treatment of IBS symptoms (very low quality of evidence)

Test Your Knowledge:

In conclusion, dietary fiber does affect bowel habits of those with IBS. Management of IBS relies on identification of symptoms, dietary lifestyle change, medical and behavioral interventions. The type of dietary fiber can change the intestinal bacteria and function of bowel pattern. Not all fiber is beneficial for those with IBS, but dietary recommendations are still maintaining fiber intakes to 25 - 30 grams daily.

1. Bijkerk CJ, de Wit NJ, Muris JW, Whorwell PJ, Knottnerus JA, Hoes AW. Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial. BMJ. 2009 Aug 27;339:b3154. doi: 10.1136/bmj.b3154. PMID: 19713235; PMCID: PMC3272664.
2. Lacy BE, Pimentel M, Brenner DM, Chey WD, Keefer LA, Long MD, Moshiree B. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021 Jan 1;116(1):17-44. doi: 10.14309/ajg.0000000000001036. PMID: 33315591.
3. El-Salhy M, Gundersen D. Diet in irritable bowel syndrome. Nutr J. 2015 Apr 14;14:36. doi: 10.1186/s12937-015-0022-3. PMID: 25880820; PMCID: PMC4436161.
4. What is irritable bowel syndrome (IBS. (2023, August 11). What is irritable bowel syndrome (IBS)? YouTube. https://youtu.be/HOq4GwPB8Mk
5. ‌How, I. (2023, August 11). What causes irritable bowel syndrome (IBS)? How does IBS start? YouTube. https://youtu.be/PmTgdReJpbY
6. ‌are, W. (2023, August 11). What are the symptoms of irritable bowel syndrome (IBS)? YouTube. https://youtu.be/z9SZK47jPPI
7. ‌Why. (2023, August 11). Why is IBS difficult to diagnose? What other conditions can look like IBS? YouTube. https://youtu.be/Fvu9cnsksQA
8. ‌the. (2021, April 30). Which type of fibre is the best for IBS? YouTube. https://youtu.be/edkeEFEv5t0?si=fTWQzcZoI3CEFMCT

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