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Evidence Based

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The Truth About Crohn’s Disease and Dietary Fiber

Written by Dr. Ruscio on July 5, 2022

Written by Dr. Ruscio on July 5, 2022 — Reviewed by Hannah Hamlin

Dietary Fiber Tolerance Is Different for Everyone

• Dietary Fiber for Crohn’s Disease|
• Does Dietary Fiber Help Crohn’s Disease?|
• Elemental Diet|
• Low FODMAP Diet|
• Dietary Fiber and Short-Chain Fatty Acids|
• Healing Has Ups and Downs|

Besides the physical symptoms of Crohn’s disease, one of the most difficult things is just knowing what you should or shouldn’t eat. What foods will keep intestinal inflammation to a minimum, while still providing the nutrition of a healthy diet? What is safe for your digestive tract and gut microbiota, and what should you avoid?

Many people know that  gluten, spicy foods, or lactose are possible triggers, but what about your intake of dietary fiber? Despite their “healthy” status, certain carbohydrates like whole grains, fibrous vegetables, and dense starches may be just as difficult for your gut to process as more obvious trigger foods.

How much dietary fiber you should eat with Crohn’s disease depends on several factors: whether you are going through a Crohn’s disease flare, your nutritional status, any microbial disruptions in the gut, and your personal tolerance to certain foods. There is no one answer for everyone, but through a little dietary experimentation, you can figure out how much dietary fiber is best for you with Crohn’s disease.

Let’s dig deeper into the effects of dietary fiber on Crohn’s disease, soluble vs. insoluble fiber for Crohn’s disease, and dietary strategies to help your gut handle more fiber.

Crohn’s Disease: Dietary Fiber for Prevention

Most of the evidence for consuming dietary fiber in relation to Crohn’s disease has to do with preventing the disease from occurring in the first place. 

Several systematic reviews and meta-analyses (the highest quality of research) have shown that dietary fiber consumption can reduce the risk of developing Crohn’s disease [1, 2, 3]. Healthy eating patterns that are generally higher in fiber, such as a Mediterranean diet, may also help reduce the risk of developing IBD [4].

Specifically, a 2021 SR/MA of six observational studies found that consuming more fruits and vegetables was associated with a lower risk of ulcerative colitis and Crohn’s disease (inflammatory bowel disease or IBD) [2].

Another review attempted to describe the benefits of dietary fiber on general health. The results showed that dietary fiber may be associated with a reduced risk of colon cancer and Crohn’s disease, which suggests that fiber intake is good for the gut [1].

These are not novel findings, but it’s worth the reminder that at least some dietary fiber is typically good for your gut as long as you don’t have digestive problems, whether you are looking to prevent digestive disease or you’ve already done some healing of your gut. 

Does Dietary Fiber Help With Crohn’s Disease?

Whether or not dietary fiber is helpful for treating or managing Crohn’s disease is a more complicated story. 

The research is quite mixed on this question. One research review that examined several diets for IBD, including high fiber diets, was unable to conclude whether or not high fiber intake is helpful or harmful for IBD [5].

This is a case where we may have to look more closely at individual responses to assess the effectiveness of a therapeutic intervention.  

IBD patients often report that high fiber foods worsen their symptoms [6, 7, 8]. Additionally, the European Society for Clinical Nutrition and Metabolism (ESPEN) states that a high fiber diet is NOT recommended to maintain remission of Crohn’s disease [9], and they note that a diet low in insoluble fiber could be helpful for Crohn’s patients with intestinal stenosis (abnormally narrow parts of the GI tract created by intestinal scar tissue).

In contrast, one literature review noted that dietary fiber from fruits, vegetables, cereals, grains, nuts, and seeds may be helpful for IBD patients except for in the presence of a bowel stricture [10].

Another review stated that there is no evidence to restrict fiber in IBD patients without intestinal strictures or obstructions, but it was noted that insoluble fiber may be less effective than soluble fiber [11].

Interestingly, when research has isolated fiber to supplemental form (as opposed to dietary fiber like fruits and vegetables), it does not appear to help improve Crohn’s disease activity [12]. But again, this is not going to be true in all cases; the response to fiber is very individualized. Overall, the relationship between fiber and Crohn’s is not fully understood [13]. Based on the above research, some level of dietary experimentation may be best to help determine if fiber is helpful or harmful for someone with Crohn’s disease. Patients may do well to try an elemental diet or a low FODMAP diet to restrict certain fibers that are highly fermentable [14, 15].

Soluble vs. Insoluble Fiber

One important distinction to make is the difference between soluble and insoluble fiber [11]. Soluble fiber may be a better option for Crohn’s disease because it draws water into the stool, both slowing down digestion and making the stool easier to pass.

Since diarrhea is a major concern for most people with Crohn’s, slowly adding more soluble fiber to their diet may be beneficial.

Insoluble fiber, however, does not absorb water and may be more difficult to digest with Crohn’s disease.

Elemental Diet for Crohn’s Disease

An elemental diet, which consists of a nutrient-dense, anti-bacterial, and easy-to-digest meal replacement shake, is one of the most effective therapies for reducing Crohn’s disease symptoms [16].

You don’t have to use an elemental diet for a long period of time. In fact, it’s designed to be a short-term bridge to get your gut back on track so that you can add more nutritious foods into your diet. 

An elemental diet may also be paired with antibiotic or antimicrobial therapy when infections are a concern. This was helpful for Matt, a patient at the Ruscio Institute, in the beginning of his gut healing journey with Crohn’s disease.

An elemental diet is about as low-fiber as you can get, and in my clinical experience, it is often necessary to kick off the initial healing process, or it can be used as a maintenance therapy in later stages of healing.

Low FODMAP Diet for Crohn’s Disease

Another option for those who are sensitive to certain dietary fibers is a low FODMAP diet.

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols. These are different types of fermentable starches and sugars found in certain foods in higher or lower amounts.

As the name suggests, the low FODMAP diet prioritizes low FODMAP foods that are less prone to trigger digestive symptoms like bloating, gas, diarrhea or constipation, cramping, and abdominal pain.

The low FODMAP diet may be a good compromise for Crohn’s patients to consume some dietary fiber, but avoid fermentable fibers that may trigger symptoms.

You can read more about the low FODMAP diet in this article, or in my book Healthy Gut, Healthy You.

Dietary Fiber and Short Chain Fatty Acids (Butyrate)

One potential benefit to consuming more fiber is increasing the number of short-chain fatty acids, especially butyrate, in your gut. Butyrate is a postbiotic metabolite (a nutrient made by probiotics in your gut) that nourishes the gut lining and supports the microbiome. 

Butyrate-producing gut bacteria manufacture butyrate in the large intestine by munching on certain prebiotic fibers called resistant starches. You can also get some pre-made butyrate from dairy products, especially butter.

There’s some mixed data on the benefits of butyrate for IBD patients, but some studies do find benefit to the microbiome and gastrointestinal symptoms from increasing it [17, 18].

Fiber May Have a Role in Healing Crohn’s

Whether or not you are able to incorporate more dietary fiber with Crohn’s disease may depend on what stage of healing you are in. If you are just at the beginning of the journey, a low-fiber diet may be more beneficial than a high-fiber diet. 

But once you have done some foundational healing, you may be ready to handle more dietary fiber. Doing so may support your microbiome, provide more nutrients (if you’re eating more fruits and vegetables), and help prevent future flare-ups. 

As Matt discovered, healing from Crohn’s disease isn’t linear. Remember that healing comes in peaks and valleys, and one treatment or diet that has worked for you in the past may work differently now. You may make some progress, regress, and find something else that pushes your healing forward. 

This is a good thing – it shows our gut has the ability to change and adapt. If you aren’t able to handle much dietary fiber right now, gut healing can enable you to expand your diet in the future. 

For more information on healing your gut, diet, and fiber, check out my book Healthy Gut, Healthy You.

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