- Fiber is an important part of a healthy diet for most people, aiding and protecting the body in numerous ways.
- More than 6 million people globally have irritable bowel disease (IBD).
- Researchers from two universities in Canada have found certain types of fiber can worsen symptoms for people with IBD.
- Scientists are using their findings to develop a simple stool test to provide dietary guidelines for people with IBD.
Now researchers from the University of Manitoba and the University of Alberta in Canada report they have found evidence suggesting certain types of dietary fiber can actually worsen IBD symptoms. The research team is using their findings to develop a stool test to provide an eating guide for people with IBD to help them avoid symptom flares.
More than 6 million people globally have IBD, which is an umbrella term for two conditions caused by inflammation within the digestive system. These two conditions are Crohn’s disease and ulcerative colitis.
Crohn’s disease normally develops in either the small or large intestine while ulcerative colitis affects the large intestine, also known as the colon.
Common symptoms of IBD include:
Many times people use the terms IBD and IBS (irritable bowel syndrome) interchangeably. Although both IBD and IBS share some of the same symptoms, they are different as IBS does not cause visible damage or inflammation to the digestive tract.
IBD is normally diagnosed by a doctor through stool samples, blood tests, and/or endoscopic procedures such as a colonoscopy.
There is currently no cure for IBD. Doctors treat people with IBD with medications to help reduce and manage symptoms.
Dr. Heather Armstrong, an assistant professor in the Department of Internal Medicine at the University of Manitoba, Canada Research Chair in Integrative Bioscience, and lead author of the new study, told Medical News Today this research was driven by a desire to better understand the reason why certain people with IBD express intolerance to a high-fiber diet.
“Fibers are not digested. They are fermented by
According to Dr. Stephanie L. Gold, a gastroenterologist at Mount Sinai Hospital in New York and an instructor of medicine at the Icahn School of Medicine at Mount Sinai who was not involved in the study, the use of dietary fiber in people with IBD has been controversial.
“In the past, most providers recommended that patients with IBD should avoid all types of fiber, as this was thought to worsen symptoms,” she told MNT. “However, we now recognize the potential benefits of fiber, especially
“As we are learning more about the benefits of fiber and how these indigestible carbohydrates interact with the microbiome through fermentation, we will need to identify which patients would benefit from increasing the fiber in the diet and which type of fiber is most beneficial as well as easily tolerated,” Gold added.
In this study, Armstrong and her team — including Dr. Eytan Wine, a professor in the Department of Pediatrics at the University of Alberta, Canada — analyzed colonic biopsies and other tests from people with IBD to analyze the effect of certain types of fibers on their bodies.
Upon analysis, researchers said they found unfermented dietary β-fructan fibers caused an inflammatory response in participants with IBD whose bodies were unable to break down the fiber. Dietary β-fructan fibers are a type of soluble fiber found in fruits and vegetables. Soluble fibers can dissolve in water and help a person feel full longer after eating.
The research team is now using the study results to develop a stool test a doctor could use to check people with IBD for the microbes needed to properly break down certain types of fiber. This information could help doctors customize an appropriate diet for each IBD patient.
“By creating this stool test, we are hoping to be able to tell you how to adjust your diet to prevent flares or further worsening,” Wine said. “It’s a dynamic situation so it’s possible that a certain food you should avoid now, in a few months you’ll be OK to eat that again.”
Gold said as a physician focused on IBD and nutrition, she found this study promising as it identified a potential link between fiber and microbial fermentation in the gastrointestinal tract that could help doctors’ understanding of why certain people with IBD may or may not benefit from fiber intake.
“This is a great step toward precision nutrition and hopefully in the future, we can use this study and future studies in this area to provide recommendations for individuals with IBD about what types of fibers they should include in the diet and when in the disease course this would be most beneficial,” she added.
MNT also spoke with Dr. James East, a gastroenterologist at Mayo Clinic Healthcare in London, who said this study correlates with what IBD patients have been reporting for many years — that fiber can make their symptoms worse.
“It may also explain why prebiotics have been less effective than expected in clinical studies in IBD patients,” he added.
For the next steps in this research, Gold would like to see further studies on the impact of different dietary fibers in people with IBD, “identifying which specific fibers are beneficial and which are potentially harmful at different times in the disease course.”
And East said it seems that changes in the microbiome of IBD patients correlate with their response to fiber, “and so it would be very exciting to see if the researchers could use microbiome analysis to predict which IBD patients would benefit from fibers and who should avoid them.”