Fiber for IBD: Why It Helps, Best Types, and How to Boost Your Fiber Intake

Fiber is an important component of a healthy diet. However, those living with an inflammatory bowel disease (IBD) like Crohn’s disease or ulcerative colitis (UC) may avoid fiber-rich foods out of fear that they may worsen gastrointestinal (GI) symptoms.

Luckily, research has demonstrated that fiber can actually help to lower inflammation, improve gut microbiome health, reduce the risk for colorectal cancer, and even aid in GI symptom management.

That said, fiber comes in many different forms, some of which are especially beneficial for GI issues, while others may be irritating for some people with sensitive GI tracts. Each individual is unique, so before increasing your fiber intake, there are a few considerations to keep in mind.

Here’s everything you need to know about fiber, why it helps, the best types of fiber to incorporate into your diet if you have IBD, and which types of fiber are more likely to provoke IBD symptoms.

Fiber is a type of carbohydrate that the body cannot digest. It’s naturally found in foods like:

• Fruits and vegetables
• Beans and legumes
• Nuts
• Seeds
• Whole grains

It passes through your GI tract mostly intact, and plays a number of key roles in maintaining overall health, including digestive health, weight maintenance, and regulation of cholesterol and blood pressure.

“Mechanical irritation refers to the physical abrasion of the inflamed gut lining caused by coarse or bulky foods,” says Ritu Nahar, MD, a gastroenterologist with Allied Digestive Health in New Jersey. “During IBD flares, the intestinal lining is inflamed and often ulcerated, making it more susceptible to irritation.”

However, these recommendations were not based on actual scientific evidence, but on anecdotal reports of patients who felt better after removing fibrous foods from their diets. Forgoing fiber could actually have detrimental effects for people with GI issues like Crohn's disease or UC.

When it comes to how much fiber people with IBD should consume, it’s not always straightforward, says Paula Prieto-Jimenez, MD, a pediatric gastroenterologist at Phoenix Children’s in Arizona.

“There are many myths about whether fiber is good or bad for you, and providing clinical advice is not always black and white,” says Dr. Prieto-Jimenez. “Before providing recommendations to patients, it is important to understand the status of the IBD diagnosis, where the disease is located, and whether it’s in remission versus active disease. You also need to evaluate the types of fiber (soluble versus insoluble) and what exactly you are trying to accomplish by consuming the fiber.”

While fibrous foods like fresh fruits and vegetables may sound like a bad idea when your GI tract is inflamed, some fiber types found in certain plant foods are gentle on the gut and unlikely to worsen irritation. And in the long run, fiber can have several health benefits for people with IBD.

Fiber Is Associated With Reduced Inflammation and Increased Remission

One reason: “Soluble fiber can serve as a prebiotic, feeding beneficial gut bacteria that produce short-chain fatty acids (SCFAs), such as butyrate,” says Nahar. “SCFAs have anti-inflammatory properties and can help maintain the integrity of the gut lining.”

Fiber Is Associated With Reduced Colorectal Cancer Risk

Fiber Is Linked to a Better Composition of Gut Microbes

“Fiber improves the microbiome diversity … and reduces the risk of flares,” says Prieto-Jimenez.

“When talking about fiber, it’s always important to consider the type, texture and amount,” says Prieto-Jimenez. “During an IBD flare-up, the intestine does not absorb well, and anything harder to digest irritates the intestine and prolongs healing time.”

Types of fiber that are gentle on the gut during a flare include:

Soluble Fiber

“Soluble fiber will help bulk up the stool and will result in good intestinal transit with less mechanical impact,” says Prieto-Jimenez.

• Instant oatmeal
• White rice
• White or sourdough bread
• Polenta
• Potatoes without skin
• Winter and summer squash varieties
• Smooth nut butters
• Hummus
• Bananas

“The preparation method [such as cooking until soft] also plays a significant role in tolerance,” says Nahar. Prieto-Jimenez recommends cooking vegetables until they’re fork-tender or blending them into a smoothie or juice.

“Overall, people with IBD should incorporate all types of fiber in their diet.” That said, if you’re experiencing a flare, it helps to limit certain types of fiber until your symptoms improve. These include:

Insoluble Fiber

“Insoluble fiber or fiber consumed in large quantities during active inflammation can [worsen] symptoms by irritating the gut lining and increasing stool bulk, which may lead to discomfort or diarrhea,” says Dr. Nahar.

• Wheat bran
• Whole nuts and seeds
• Leafy greens
• Legumes
• Quinoa
• The skins of fruits and vegetables

Those actively experiencing IBD symptoms often benefit from reducing their intake of insoluble fiber and replacing it with foods rich in soluble fiber instead. For example, swapping out berries for bananas, or opting for oatmeal rather than bran cereal.

Still, this is highly dependent on personal factors, Prieto-Jimenez says. “When someone is going through an IBD flare-up, adjusting fiber depends on symptoms, disease location, and type to define the best individualized plan,” she says.

FODMAPs

• Legumes
• Wheat
• Lactose-containing dairy
• Processed and marinated meat
• Certain fruits
• Vegetables like onions, garlic, artichokes, mushrooms, and cauliflower
• Fruits, especially stone fruits like peaches, avocado, and cherries
• Sugar substitutes

Everyone’s FODMAP tolerance is unique, so it’s helpful to work with a registered dietitian to pinpoint which FODMAPs may trigger your symptoms specifically and which ones you should limit during a flare.

As mentioned, fiber needs among people with IBD are highly individualized, says Nahar. “Working with a gastroenterologist and a registered dietitian can help patients navigate dietary choices and make adjustments based on their unique symptoms and disease state. Education on fiber types, preparation methods, and symptom monitoring can empower patients to manage their condition more effectively,” she says.

When upping your fiber intake, it can help to follow these three tips:

1. Start Slow

It’s best to start “slow and low,” gradually increasing the amount and variety of fiber-rich foods you eat over time. This allows your GI tract and gut microbes to adjust.

“Gradually increasing fiber intake involves introducing small amounts of fiber-rich foods over time to allow the gut to adapt,” says Nahar. “This could mean starting with easily digestible, low-FODMAP fiber sources like zucchini or oats.”

Increasing your fiber intake too quickly can lead to GI discomfort. As mentioned, it’s also helpful to lean toward soluble over insoluble fiber sources, which tend to be better tolerated during IBD flares.

2. Monitor Your Symptoms as You Increase Your Fiber Intake

Nahar suggests tracking your symptoms with a food and symptom diary to help identify how much fiber you can tolerate and avoid overloading your gut. Look for and note symptoms like:

• Bloating
• Cramping
• Gas
• Irregularity in the timing of bowel movements
• Changes in the size, shape, and color of your stool

3. Adjust Your Fiber Intake in Response to IBD Flares

During a flare:

• Focus on low-residue, easily digestible foods, like meat, fish, eggs, and white rice.
• Avoid raw fruits and vegetables, whole grains, and high-fiber legumes.
• Opt for peeled, cooked, and pureed options.
• Modify food textures by blending, pureeing, or mashing.

During remission:

• Gradually reintroduce fiber, prioritizing soluble sources like oats, avocados, and well-cooked vegetables. “By focusing on soluble fibers and preparing foods in ways that reduce their rough texture [such as cooking, peeling, or pureeing], patients can minimize irritation and support healing,” Nahar says.
• Monitor tolerance and avoid trigger foods.

• Managing your fiber content can reduce GI symptoms and support overall gut health.
• Monitoring your fiber intake and gradually incorporating high-fiber foods you can tolerate into your meals can help reduce inflammation and possibly even lead to symptom remission.
• Be careful about introducing insoluble fiber and FODMAPs, as they may trigger flares.
• Opt for soluble fiber from foods like bananas and oatmeal and cook your foods well.

Additional reporting by Crystal Hoshaw.