• Some research shows that fiber may help prolong periods of UC remission and offer other benefits.
  • However, consuming insoluble fiber can make UC symptoms worse during a flare.
  • Talk with a healthcare professional or dietitian before adjusting the levels of fiber in your diet.

Diet doesn’t cause or cure ulcerative colitis (UC), but what you eat can make a difference in your symptoms and flares. Fiber, in particular, has a complicated link to UC that’s worth taking a closer look at.

Information on how fiber can affect UC is often conflicting. It’s complicated further by the fact that not all fiber is the same. There’s soluble fiber, which dissolves in water and gastrointestinal (GI) fluids, and insoluble fiber, which remains unchanged as it moves through your GI tract.

The Crohn’s and Colitis Foundation considers foods rich in insoluble fiber a potential trigger for UC. But a 2020 study found that a low fat, high fiber diet improved quality of life for people with mild UC or UC in remission.

Should people with UC avoid fiber or increase the amount of this nutrient in their diet? Keep reading to learn more about how fiber can affect UC.

Some research has shown that fiber may be beneficial for managing ulcerative colitis during periods of remission.

According to research from 2015, dietary fiber can prolong remission from UC and reduce lesions in the intestines by reducing activity in mucosal mast cells. These cells are key to helping your gut function and maintaining your intestinal barrier, but they may trigger an immune response, which leads to inflammation.

A study from 2003 found that 22 people with UC in remission experienced no gastrointestinal complaints or UC relapses when they ate 60 grams of fiber-rich oat bran per day for 3 months.

The study from 2020 mentioned earlier found that participants with mild UC or UC in remission who ate a low fat, high fiber diet experienced reduced inflammation and improved quality of life. The research included only 17 people, though, so the findings may not apply to a larger population.

Fiber generally isn’t considered helpful during UC flares. The UK’s National Health Service suggests following a low fiber diet to help improve symptoms of UC during a flare-up.

Either way, it’s a good idea to check in with a doctor or dietitian before reducing or increasing the amount of fiber in your diet.

Fiber can aggravate symptoms during a UC flare for some people. This is particularly true with insoluble fiber, which doesn’t dissolve in water.

According to the Crohn’s and Colitis Foundation, consuming insoluble fiber can worsen symptoms like:

  • bloating
  • gas
  • diarrhea
  • abdominal pain

It may even lead to a blockage in the intestinal tract if you have severe inflammation.

Limiting food with insoluble fiber may be beneficial for people with an inflammatory bowel disease (IBD) like UC.

If fiber seems to worsen your symptoms, you may consider switching to a low fiber diet during a flare. Eating less fiber can help reduce the frequency of your bowel movements and the amount of stool you pass, according to the National Health Service.

You may want to steer clear of the following fiber-rich potential trigger foods during a flare:

  • fruits with skin and seeds
  • raw green vegetables
  • cruciferous vegetables (like broccoli and cauliflower)
  • whole nuts
  • whole grains

You can also try different techniques to make fiber easier to digest or reduce the amount of fiber in a food. The Crohn’s and Colitis Foundation recommends cooking veggies until they’re tender, peeling fruits and veggies, and discarding seeds to help cut back on insoluble fibers.

Eliminating nutrients from your diet can have a negative impact on your health. Consider working with a doctor or dietitian to make sure a low-fiber diet is safe for you.

Fiber is a type of carbohydrate found in fruits, vegetables, legumes, and grains. It can’t be digested, but research from 2009 shows fiber offers a number of health benefits, such as:

  • reducing blood pressure
  • reducing cholesterol levels
  • improving insulin sensitivity
  • helping people with obesity lose weight
  • enhancing immune function

Fiber comes in two different forms: soluble and insoluble. Both types are important for good nutrition.

Soluble fiber can dissolve in water and gastrointestinal fluids. When you consume soluble fiber, the colon breaks it down into a gel that’s then digested by gut bacteria.

You can find soluble fiber in foods like:

  • oats
  • black beans
  • lima beans
  • avocado
  • pears
  • nectarines
  • carrots
  • sweet potatoes
  • broccoli
  • hazelnuts
  • sunflower seeds

Insoluble fiber can’t dissolve in water or other fluids, which means it remains mostly intact during digestion. It helps form stools and prevent constipation. The following foods are rich in insoluble fiber:

  • wheat bran
  • whole grains
  • cauliflower
  • potatoes
  • green beans
  • nuts

The Food and Drug Administration (FDA) recommends that adults consume 28 grams of fiber per day.

Fiber plays an important role in nutrition, but it can worsen UC flares in some people. Understanding how fiber affects your symptoms can help you figure out what to eat during flares and in remission.

Before changing the amount of fiber you eat, talk with your doctor or dietitian. They can help you adjust your diet safely and ensure you’re getting the right amounts of nutrients.