New research conducted by the University of Chicago pathology department on peanut allergies may be closing in on an answer to what causes human allergies to the burrowing legume.

The research by Andrew T. Stefka, Taylor J. Feehley, professor Cathryn R. Nagler, and others suggests that peanut allergies are in large part caused by lack of a specific microbiota, a type of bacteria, that plays a large role in protecting against potential allergens.

Nagler and her team’s research was based on trials with mice. It builds upon another set of research from other labs, which has shown that there is bacteria near the epithelial barrier (a part of the colon) that generate regulatory T cells, which are cells that control immune response.

This new research shows that these specific bacteria are multi functional. Not only do they produce T cells to block allergens, but they also actively block the same foreign invaders from entering the bloodstream by creating a barrier between the inside of the colon and the bloodstream. This dual role heightens their importance and means the lack of these bacteria inside the body can be especially detrimental.

Although these studies were done in mice, Nagler said that “we already have data… that hasn’t been published yet, from healthy and allergic children that shows that their microbiota is quite different.”

There is already work being done by researchers on humans with severe peanut allergies to “desensitize allergic kids with small amounts of the allergen that they’re allergic to,” Nagler said. “It works but not very well. What we’re suggesting is that if you pair that with barrier fortification that [these bacteria] provide, we might be able to do a better job at desensitization.”

Nagler suggested that the reason people have peanut allergies and thus have fewer of these gut bacteria is a feature of the developed world; genetics cannot explain the rapid rise in peanut allergies over the last few generations.

“[An increase in the incidence of human peanut allergies] can’t be explained by genetics. Genetics [don’t] change that quickly,” Nagler said. “There are environmental factors that have depleted populations of bacteria that live in our gut that sort of have a protective role against allergic responses.”

According to the researchers, the factors which contributed to a decline in gut bacteria include unnecessary antibiotic treatments for ear infections and the consumption of animals fattened by use of non-pharmaceutical grade antibiotics.