How Pomegranates May Help the Gut Repair Itself After Injury

Researchers from the University of Louisville have uncovered how a natural compound produced by gut bacteria after digesting certain foods helps protect the intestine from damage. The findings, published in the journal Nature Communications, could pave the way for new treatments for inflammatory bowel diseases.

Inflammatory bowel diseases (IBD), including Crohn's Disease and Ulcerative Colitis, affect millions of people worldwide. These conditions are characterized by chronic inflammation and damage to the intestinal lining. As a result, the intestinal barrier—which normally prevents harmful microorganisms and toxins from entering the body—becomes compromised.

The researchers focused on a compound called urolithin A. This molecule is produced by gut bacteria when they break down compounds found in pomegranates, walnuts, berries, and certain other plant-based foods.

The team discovered that urolithin A activates a specialized protein known as the aryl hydrocarbon receptor (AHR), which functions as a sensor for signals originating from the environment, diet, and the gut microbiome.

Scientists already knew that activation of this receptor could produce either beneficial or harmful effects, but the mechanism determining the outcome had remained unclear.

The new study revealed that the key factor is the type of cell in which the receptor is activated. Urolithin A selectively targets intestinal epithelial cells—the cells that form the protective lining of the gut.

Within these cells, activation of AHR triggers the NLRP6 inflammasome, a molecular complex traditionally associated with inflammatory responses. However, the researchers found that in this context the system behaves quite differently.

Under the influence of urolithin A, the inflammasome promotes the release of molecules that help repair damaged intestinal tissue, strengthen the gut barrier, stimulate the production of protective mucus, and enhance antimicrobial defenses. Rather than driving inflammation, the pathway activates mechanisms involved in tissue healing and restoration.

According to lead author Sweta Ghosh, the findings demonstrate that not all inflammatory signaling pathways are harmful.

“Under the right conditions and in the right cells, these mechanisms can play a critical role in maintaining gut health and repairing tissue,” the researcher noted.

The scientists confirmed their results not only in cell models and organoids but also in intestinal tissue samples obtained from patients with inflammatory bowel disease. In each case, urolithin A activated the same protective biological pathway.

The authors believe the discovery could reshape approaches to treating inflammatory bowel diseases. Most current therapies work by broadly suppressing the immune system, often leading to significant side effects. The newly identified strategy focuses instead on activating specific protective mechanisms within particular cell types while preserving normal immune function.

Study leader Venkatakrishna Rao Jala emphasized that the findings highlight the importance of the interaction between diet, gut bacteria, and human physiology.

According to the researchers, further investigation of urolithin A and its associated signaling pathways may lead to more precise and safer treatments for inflammatory bowel diseases—therapies aimed not at suppressing immune responses but at restoring the gut’s natural balance and protective functions.

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