Some research suggests that fiber may help prolong periods of UC remission and offer other benefits. But talk with a healthcare professional or dietitian before adjusting the amount of fiber in your diet.

Eating certain foods 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 a closer look.

Information on how fiber can affect UC is often conflicting. And it’s further complicated by the fact that not all fiber is the same. There are two types: 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. However, the results of a small 2021 study suggest that a low fat, high fiber diet may improve quality of life for people with mild UC or UC in remission.

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

Some research suggests that fiber may be helpful for managing UC during periods of remission.

In the 2021 study mentioned earlier, participants with mild UC or UC in remission who ate a low fat, high fiber diet experienced reduced inflammation and improved quality of life. But that study included only 17 people, so the findings may not apply to a larger population.

Fiber generally is not considered helpful during UC flares. The United Kingdom’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 a registered dietitian before significantly reducing or increasing the amount of fiber in your diet.

For some people, fiber can worsen symptoms during a UC flare. This is particularly true of insoluble fiber, which doesn’t dissolve in water.

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

  • bloating
  • gas
  • diarrhea
  • abdominal pain

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

Limiting your intake of foods that contain insoluble fiber may be beneficial if you have an inflammatory bowel disease such as UC.

If fiber seems to make your symptoms worse, you might consider switching to a low fiber diet during UC flares. Eating less fiber can help reduce the frequency of your bowel movements and the amount of stool you pass.

You may want to avoid the following fiber-rich during a flare, as they could trigger UC symptoms:

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

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

However, removing nutrients from your diet can have a negative impact on your health. Consider working with a doctor or a registered 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 it offers a number of potential health benefits, such as:

  • reducing blood pressure
  • reducing cholesterol levels
  • improving insulin sensitivity
  • promoting weight loss in people with obesity
  • enhancing immune function

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

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

You can find soluble fiber in foods such as:

  • 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 stays 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 periods of remission.

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