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By Colleen D. Webb, MS, RDN, CLT

If I had a dollar for each time a patient told me that someone informed them that food has nothing to do with their inflammatory bowel disease (IBD) then I’d be writing this post from my own private island.

The notion that food has no effect on IBD is bonkers, yet it’s one of the most common pieces of advice given to patients.

Another popular bit of advice? Avoid whatever bothers you and eat what doesn’t. This implies that food’s only role in IBD is symptom management. That’s important, but it’s only one reason to consider dietary changes as part of your overall IBD treatment plan.

Let’s set the record straight. What you eat directly and indirectly affects your immune system, inflammation and, ultimately, the course of your IBD. This may be contrary to what you’ve read or heard regarding nutrition and IBD, but it’s science.

To better understand nutrition’s role in managing IBD, it’s helpful to review some IBD basics.

What is Inflammatory Bowel Disease?


Inflammatory bowel disease is a lifelong, systemic, relapsing immune-mediated inflammation of the gastrointestinal (GI) tract. IBD affects roughly 1.6 million Americans and millions more worldwide. It can present at any age and affects both males and females.

The two main types of IBD include ulcerative colitis (UC) and Crohn’s disease.

In UC inflammation is limited to the colon and almost always involves the rectum. In Crohn’s disease inflammation occurs anywhere from your mouth to your bottom, but it most commonly affects the ileum and/or colon.

People with UC commonly complain of frequent and urgent diarrhea with or without blood, but they can struggle with constipation and incomplete evacuation. Crohn’s symptoms vary based on the location of inflammation but often include abdominal pain, diarrhea, and weight loss. Extraintestinal manifestations, including mouth sores, joint pains, and anemia, can also occur.

For this article, we will refer to UC and Crohn’s disease as IBD.

Please note that IBD is not IBS. IBS stands for irritable bowel syndrome. People with IBD can have overlapping IBS but IBS is not the focus of this article.

What Causes IBD?

That’s the million dollar question.

We don’t know what causes IBD, but we know that both nature (genetics) and nurture (environment) play a role in the development and reactivation of the disease. You must be genetically susceptible and exposed to certain environmental triggers. That is to say genetics loads the gun, but environment pulls the trigger.

Here’s a list of potential environmental triggers, in no particular order.


• Stress

• Infections

• Medications, such as antibiotics and nonsteroidal anti-inflammatory drugs (e.g. aspirin)

• Hygiene (i.e. are we too clean?)

All of these, including what we eat, can disrupt the balance of the gut microbiome, upset the intestinal mucosal barrier, and promote an inappropriate immune response.

Your gut’s immune system and microbiome work together to support a strong intestinal barrier to help protect you from potentially harmful invaders, such as bacteria, toxins, and undigested food particles.

Most non-medical professionals call this loss of barrier function “leaky gut” whereas medical professionals refer to it as “increased intestinal permeability”. Leaky gut increases your risk of developing IBD and precedes IBD flares.

Some major goals of IBD therapy are to restore gut barrier function, promote microbial diversity, and reduce inflammation. What we eat can help or hinder these processes.

Diet & Poor Gut Health

Research suggests that the following dietary patterns, foods and food additives weaken the intestinal barrier and disrupt the gut microbiome:

• Energy-dense diets (i.e. consuming too many calories)

• Diets high in animal fats and sugars (i.e. “The Western Diet”)

• Food additives: carrageenan, Polysorbate 80, carboxymethylcellulose (these are easy to avoid by avoiding highly processed foods)

• Vitamin A deficient diets

• Low-fiber diets

• Personalized food sensitivities

Unsurprisingly, most of these are the same factors that researchers suspect increase one’s risk of developing IBD, whereas diets high in fruits and vegetables, and low in sugar, highly processed foods, and animal fats might protect against IBD.

Proof that Diet Directly Affects IBD Flares

Basic science principles and common sense aside, is there proof that diet directly impacts IBD?

You betcha!

One of the best arguments to support diet’s role in IBD comes from research on exclusive enteral nutrition and pediatric Crohn’s disease.

Exclusive enteral nutrition (EEN) involves the use of a 100% liquid diet without normal dietary components for a defined time period.

Oodles of studies published over the last 10-20 years have showed how EEN can lead to high rates of clinical remission (~85%) and mucosal healing in children and adolescents with active Crohn’s disease. Research has shown EEN to work as well as steroids but without steroids’ brutal side effects. However, physicians rarely use EEN in the United States even though The North American Society of Pediatric Gastroenterology Hepatology and Nutrition recommends it as first-line therapy. Lack of education among health care providers and non-compliance among patients contribute to its limited use.

EEN isn’t the only nutrition therapy for IBD that’s backed by research. Research shows the Specific Carbohydrate Diet (SCD), a popular dietary approach for IBD, to result in clinical and mucosal improvements in children with Crohn’s disease.

The SCD removes grains, starchy vegetables, lactose, soy, and most beans, sugars and food additives. Its focus is on nutrient-rich foods, including vegetables, fruits, nuts, meat, and fish.

Research suggests that these dietary interventions work because they alter the gut microbes, enhance gut barrier function, and fight inflammation through the elimination of some components of regular table food.

Key Takeaways About How Diet Affects IBD

In our eBook, Eating with IBD: The Essentials, we summarize 7 major ways that food impacts your IBD:

1. A healthy gut requires proper nutrition.

2. Your gut microbes directly affect your immune system and inflammation, and what we eat directly affects our gut microbes.

3. People with IBD are more likely to develop nutrient deficiencies, which we can prevent or correct through proper nutrition.

4. Some foods worsen chronic inflammation whereas others help fight it, and IBD is a chronic inflammatory condition.

5. Certain foods trigger unwanted IBD symptoms, such as gas, bloating, diarrhea and abdominal pain.

6. When you eat well for your IBD, you’re eating well for your whole body.

7. Research plus clinical and personal experience have shown us that people with IBD who eat and live well have fewer and shorter flares.


Your food choices strongly influence your IBD. There’s no doubt about it.

There’s no one perfect diet for everyone with IBD, but we hope you’ll use this information to identify health care professionals and resources to help you better understand what works for you.

We encourage you to sign up for our weekly newsletter with actionable nutrition-related tips and takeaways to improve your IBD, plus announcements about new content and products.

Check out our eBook Eating With IBD: The Essentials for more on discovering your IBD diet.

Whatever you do, please choose a gastroenterologist who values the importance of food, nutrition and lifestyle to help manage IBD. There are plenty out there!


Bhattacharyya S, et al. A randomized trial of the effects of the no-carrageenan diet on ulcerative colitis disease activity. Nutr Healthy Aging. 2017; 4(2): 181–192.

Bischoff SC, et al. Intestinal permeability – a new target for disease prevention and therapy. BMC Gastroenterol. 2014; 14: 189.

Cohen AB1, et al. Dietary patterns and self-reported associations of diet with symptoms of inflammatory bowel disease.Dig Dis Sci. 2013 May;58(5):1322-8.

Edward V. Loftus, Jr, MD. Update on the Incidence and Prevalence of Inflammatory Bowel Disease in the United States. Gastroenterol Hepatol (N Y). 2016 Nov; 12(11): 704–707.

Lewis JD1, Abreu MT2. Diet as a Trigger or Therapy for Inflammatory Bowel Diseases. Gastroenterology. 2017 Feb;152(2):398-414.e6.

Michielan A, D’Incà R. Intestinal Permeability in Inflammatory Bowel Disease: Pathogenesis, Clinical Evaluation, and Therapy of Leaky Gut. Mediators Inflamm. 2015; 2015: 628157.

Ricker MA1, Haas WC1. Anti-Inflammatory Diet in Clinical Practice: A Review.
Nutr Clin Pract. 2017 Jun;32(3):318-325.

Suskind DL, et al. Patients Perceive Clinical Benefit with the Specific Carbohydrate Diet for Inflammatory Bowel Disease. Dig Dis Sci. 2016 Nov;61(11):3255-3260.

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