Leaky gut might make food allergies worse

by American Association of Immunologists

edited by Gaby Clark, reviewed by Robert Egan

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A "leaky gut" might increase the severity of food allergies, according to new research conducted in mice and published in The Journal of Immunology. The researchers found that changes to the gut microbiome in mice were linked to increased intestinal permeability (leaky gut) and increased food allergy severity.

Intestinal permeability describes how the intestines move water and nutrients from food into the bloodstream. Increased permeability, sometimes called "leaky gut," describes a condition in which damage to the gut lining allows partially digested food, toxins or germs to pass into the bloodstream.

The gut microbiome—the trillions of bacteria living in the gut—directly regulates this barrier, meaning microbiome imbalances can be a primary driver of gut leakage.

Different mice, different reactions

In this study, the researchers used two groups of mice known to have differences in their gut microbiomes. When a food allergy was induced in the mice, one group developed mild allergic reactions (less diarrhea), while the other had more severe reactions. The mice with more severe diarrhea were also known to have increased intestinal permeability, or "leaky gut."

In mice with more severe food allergies, the researchers also observed an increase in immune cells that cause allergic reactions, Th2 cells, and a decrease in food-allergy-specific immune cells that turn off immune responses, Treg cells. Th2 cells are the immune cells that cause anaphylaxis in people with food allergies.

Shared housing changed the outcome

Interestingly, when the researchers housed mice from the two groups together, they found that mice with milder food allergies developed more severe symptoms. Further tests uncovered that the gut microbiome of the mice with milder allergic reactions shifted to be more like that of the group with severe reactions. The researchers also reported increased intestinal permeability and a change in the balance of immune cells involved in the food allergy response, suggesting that "leaky gut" and the gut microbiome are linked to how the immune system responds to a food allergy.

"Essentially, we saw that food-allergy-specific immune cells were impacted by gut microbes, which affected the food allergy itself," said Dr. Alexa Weingarden, assistant professor of gastroenterology, hepatology and nutrition at the University of Minnesota School of Medicine and lead author of the study.

New targets for allergy treatment

"Understanding how these food-allergy-specific immune cells change in response to different conditions, like the microbes in the gut, can lead to new targets for food allergy treatment," Weingarden continued.

"There's still a lot we don't know, but these findings open up new avenues for exploring interactions between gut health, immune cells and allergies. Some questions we hope to answer include which bacteria are really responsible for the difference in allergic reactions and how increased gut permeability affects food-allergy-specific immune cells," Weingarden said.

Publication details

Journal of Immunology (2026). DOI: 10.1093/jimmun/vkag172

Journal information: Journal of Immunology

Key medical concepts

Flora, Intestinal

Clinical categories

Allergy and immunologyGastroenterologyCommon illnesses & Prevention Provided by American Association of Immunologists Who's behind this story?

Gaby Clark

MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →

Robert Egan

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

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