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What If I Have Both IBS and IBD?

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It Is Common For IBD & IBS to Co-Exist

One of the happiest days in the life of someone with inflammatory bowel disease (IBD) should be when they get the good news that their disease is in remission. But, this isn’t how it plays out for everyone.

Lots of folks continue to experience intestinal symptoms despite their inactive disease. That’s because up to 40% of people with IBD also suffer from irritable bowel syndrome (IBS). It is not uncommon for IBD and IBS to co-exist. These people have a poorer quality of life compared to those with only IBD.

illustrated image of intestinal system with background filled with medical icons and text that reads "what if I have both IBS and IBD?"

So, you may ask: What if I have IBS and IBD at the same time?

Fortunately, dietary and lifestyle modifications can significantly improve IBS-related symptoms in people with IBD in remission.

The Low FODMAP Diet Can Help

In this article, I will explain how I use the low FODMAP diet to help these patients.

  • The low FODMAP diet is a clinically proven diet to help up to 75% of those with IBS.
  • The low FODMAP diet has been shown to improve ongoing symptoms in at least 50% of IBD patients in remission.

But, first, let’s review IBD and how it compares to IBS.

What Is Inflammatory Bowel Disease?

IBD is a chronic, systemic, relapsing, immune-mediated inflammation of the intestinal tract. Over 3 million people in the United States have IBD with varying levels of severity.

We don’t know what causes it, but researchers suspect a combination of genetics and environmental factors are at play.

The two main types of IBD are Crohn’s disease and ulcerative colitis.

In ulcerative colitis inflammation is in the large intestine and almost always involves the rectum. Primary symptoms include diarrhea and rectal bleeding.

In Crohn’s disease inflammation can occur anywhere along the gastrointestinal tract, but it usually involves the bottom part of the small intestine (Crohn’s ileitis), the large intestine (Crohn’s colitis), or both (Crohn’s ileocolitis). Crohn’s symptoms vary based on location, but the most common symptoms include abdominal pain and diarrhea.

Both Crohn’s and ulcerative colitis can lead to extraintestinal (out of the intestines)l complications, such as inflammation of the joints, skin and eyes.

Most people with IBD rely on medications to achieve and maintain remission. Some require surgery, including bowel resections and/or colectomy. Severe cases of IBD can lead to life-threatening complications, including colon cancer.

Graphic with two illustrations of the digestive tracts, one depicting Crohn's disease and the other depicting Ulcerative colitis

Key Similarities & Differences Between IBD & IBS

IBS is a brain-gut disorder usually involving the small and large intestines with disturbances of gut motility and sensation. Affecting approximately 45 million Americans, it is the most common functional gastrointestinal disorder.

YOU MAY WANT TO READ: The Gut-Brain Connection & IBS: It’s Not All In Your Head

informational graphic

purple graphic describing the similarities between IBD and IBS

Key differences between IBD and IBS: 

  • IBS does not require surgery.
  • IBS does not pose life-threatening complications.
  • IBS is best managed with dietary and lifestyle modifications versus medications.
  • IBS does not cause severe inflammation of the gastrointestinal tract, although it can present with low-grade inflammation.
  • IBS does not cause rectal bleeding.
  • IBS does not lead to systemic inflammation.

Key similarities between IBD and IBS: 

  • Both significantly reduce one’s quality of life and social functioning.
  • Both result in life-altering symptoms, including diarrhea, fecal urgency and frequent trips to the bathroom. Other symptoms include bloating, gas, and abdominal pain.
  • Both involve a triggering event or events that likely include one or more environmental or lifestyle factors. Examples include diet, medications, food poisoning, infections, and chronic stress.
  • Both are associated with an imbalance in the gut microbiome (dysbiosis).
  • Both are increasing in prevalence worldwide.

Since these conditions have a lot in common, it can be difficult for gastroenterologists to determine if someone’s symptoms are due to IBS or IBD.

Tests Can help Distinguish Between IBS & IBD

Doctors might use one or more of the following tests to differentiate between IBS and IBD:

  • Blood work for infection, anemia and/or inflammation.
  • Colonoscopy with biopsy.
  • Fecal calprotectin, a specific marker of intestinal inflammation.
  • Imaging, such as CT or MR Enterography.

The Low FODMAP Diet for IBD

Over the last decade I’ve counseled countless patients with IBD on what to eat. Many people see me because they continue to have symptoms despite being in remission. They need help to identify the food triggers for their overlapping IBS.

Emerging research supports using the low FODMAP diet for managing IBS-related symptoms in patients with inactive IBD, particularly for abdominal pain, bloating and gas. My clinical experience aligns with these findings.

WARNING: Patients and healthcare professionals must be cautious when using any kind of restrictive diet with this population. Nutrient deficiencies, food intolerances, and disordered eating behaviors are common among IBD patients. We must not impose unnecessary dietary restrictions.

If someone can’t do the entire low FODMAP diet, then start with just one or two groups of FODMAPs to eliminate. A registered dietitian can review one’s current diet to help decide where to begin.

Lactose intolerance is more common in people with Crohn’s and ulcerative colitis, and Crohn’s patients are less likely to absorb fructose compared to the general population. Perhaps start by eliminating lactose and/or fructose? 

Fiber & IBD

Lots of patients with active and inactive IBD limit or avoid high-fiber foods. Dietary fiber can worsen IBD symptoms. Specifically, high-roughage foods can irritate the bowel causing abdominal pain, bloating, diarrhea, urgency, and bowel obstructions in at-risk individuals. High-roughage foods include raw vegetables, whole nuts and seeds, whole grains, popcorn, and thick skins of fruits and vegetables.

a white bowl with blueberries, grapes, nuts, raspberries and kiwi on top of a white and blue napkin

Some people with inactive IBD avoid high-fiber foods out of necessity, others out of fear. Either way, many continue to feel unwell on a low-fiber diet. In lots of cases, these ongoing IBS-symptoms are because of FODMAPs.

Eat Roughage, But Go Low

I’ll recommend a low-roughage, low-FODMAP trial for 2-3 weeks. On this diet patients eat lots of low-FODMAP smoothies, white rice, soups, cooked vegetables, peeled fruit, creamy nut butters, and lean protein.

Frequently when it’s time to reintroduce or challenge foods, I’ll start with higher fiber, low FODMAP foods. Most of my patients are itching to eat more fruits and vegetables, so maybe we’ll start with a few lettuce leaves, a few carrot slices, edamame or grapes.

When these go well, they’re surprised and glad to learn that they don’t have to avoid fiber after all! From there we’ll start challenging FODMAPs. I always recommend a cautious challenge with IBD patients.

Conclusions & Key Takeaways

Up to 40% of people with IBD suffer from irritable bowel syndrome (IBS). The low FODMAP diet can improve IBS-symptoms and quality of life in these patients. 

Patients and practitioners must exercise caution when using any kind of restrictive diet with people with IBD because they are at a higher risk for nutrient deficiencies and disordered eating as compared to the general population.

Everyone on a low FODMAP diet should consult with a knowledgeable dietitian. 

One of the happiest days in the life of someone with IBD should be when they get the good news that their disease is in remission. The low FODMAP diet might be the missing link in making this a reality for IBD patients with overlapping IBS.

For those of you living with IBS and IBD, what are some of your favorite low-roughage, low-FODMAP recipes? 

Considering a low-FODMAP diet for co-existing IBS and IBD? But, not sure where to start? Submit your questions below.

We’d love to hear from you!

Meet the Author: Meet Colleen Webb, MS, RDN, CLT- Managing IBS and IBD With Nutrition and Science

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