Science is still getting to grips with understanding the gut microbiome – the rich ecosystem of trillions of microorganisms in your intestines – but an increasing number of studies are showing that it could have a surprisingly profound effect on your health and happiness. The latest study of which claims that bacteria lurking in your intestines could be the key to preventing food allergies in children.

After scientists implanted gut microbes from healthy human babies into the digestive system of germ-free mice, they noted that the animals became protected against an allergy to cow’s milk. On the other hand, when they implanted gut microbes from infants with a milk allergy into the mice, they began to suffer from allergic reactions to cow’s milk. 

Researchers at the University of Chicago, Argonne National Laboratory, and the University of Naples Federico II in Italy reached these findings thanks to the gut microbes from eight infant donors, four healthy and four with cow’s milk allergy. While the research has only been performed on mice so far, the results are promising. 

“These findings demonstrate the critical role of the gut microbiota in the development of food allergy and strongly suggest that modulating bacterial communities is relevant to stopping the food allergy disease burden,” Roberto Berni Canani, chief of the Pediatric Allergy Program at the University of Naples Federico II, said in a statement.

As reported this week in Nature Medicine, the researchers identified a single bacteria species that they believe is responsible for protection from nut and milk allergies: Anaerostipes caccae. The study notes that this bacteria produces butyrate, a fatty acid that’s used as a food for many other cells living in the guts of mammals. Armed with this knowledge, the researchers hope they might be able to develop microbiome-based treatments for people with food allergies.

Recent decades have seen a sharp rise in life-threatening food allergies in industrialized Western societies. There are many theories about why this is so, but most revolve around the idea that the 21st-century human lifestyle has become relatively germ-free; illnesses are quickly cured with antibiotics, many babies are formula-fed, and surfaces are sterilized with anti-bacterial sprays. This comparatively sterile environment means kids are not exposed to as many microbes and their intestinal bacterial communities are less diverse.

However, the art of fostering healthy gut bacteria is a fiddly and complex matter since, as this work shows, each species of bacteria might have its own unique contribution.

“What we see with this work is how, in the context of all of the different types of microorganisms inhabiting the gastrointestinal tract, one single organism can have such a profound effect on how the host is affected by dietary components,” added co-author Assistant Professor Dionysios Antonopoulos. “We also get a new appreciation for the distinct roles that each of these members play beyond the generalization that the ‘microbiome’ is involved.”