As previously mentioned, people with an IBD like ulcerative colitis are more likely to have dysbiosis — an out-of-balance microbiome. This may contribute to disease activity in UC because of a deficiency in compounds produced by beneficial bacteria, called short-chain fatty acids (SCFAs).
“Short-chain fatty acids are one of the major molecules that regulate inflammation,” both within the gut and in the body at large, says DePaolo. They do this by enhancing the effects of a type of immune system cell — known as a regulatory T cell — that helps control other T cells that are pro-inflammatory.
If you have fewer SCFAs in your body, “you’re going to have less regulation,” says DePaolo, “and that’s going to allow inflammation to be worse.” By helping healthy bacteria grow, prebiotics can help increase SCFAs and reduce inflammation.
While a number of differences in gut bacteria in people with UC have been found in scientific studies, there’s far less research showing what effect prebiotics might have on these differences, or on disease outcomes.
One research review on prebiotics examined previous studies on how different prebiotics affect inflammatory bowel diseases like UC. Although some studies showed that certain forms of prebiotics were beneficial to UC patients, the authors note that research doesn’t provide enough information to evaluate prebiotics as a treatment. Therefore, the researchers concluded that the use of prebiotics to manage symptoms of UC or maintain remission is not recommended.
This echoes another review of studies that concluded more thorough research is needed before prebiotics can be deemed effective and safe in treating UC. The review’s authors note that certain probiotic strains have been linked to positive outcomes in UC and prebiotic-rich foods are known to be beneficial for gut health, but too much remains unknown about how they work, which ones might be most beneficial, for whom, and at what dose. In addition, little is known about how such treatments might work alongside — or interact with — UC medications.
Some preliminary research, including a study on a mouse model of IBD and a small trial on 18 healthy people, has found that a certain type of prebiotic fiber called inulin can actually trigger inflammation. While the mice experienced only intestinal inflammation, most of the participants in the other study had it spread throughout their bodies — though one saw their inflammation levels decrease while taking inulin.
Trials on prebiotics have mostly used only small numbers of participants, with study designs and dosages that differ, making the results hard to compare. Additionally, many studies evaluate synbiotics — the combination of probiotic and prebiotic therapies — making it unclear what effect prebiotics by themselves would have had.
While the research may be inconclusive on any benefits regarding UC, prebiotics are naturally tied to healthy and nutritious food options, and may still support overall gut health.
