In the latest study, Italian and US doctors took gut bacteria samples from healthy babies, and babies allergic to cow’s milk, and transplanted them into mice that had been bred in a sterile environment – meaning they had no bacteria of their own.
When the mice were exposed to cow’s milk, those that had received gut bacteria from children with allergies and those who had received no bacteria suffered anaphylaxis – a potentially life-threatening immune response.
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However the mice that had been transplanted bacteria from healthy children did not experience any adverse reaction.
“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,” said Dr Roberto Berni Canani, who heads the paediatric allergy programme at University Federico II, Naples and was a senior author of the study published in Nature Medicine.
“These data are paving the way for innovative interventions for the prevention and treatment of food allergy that are under evaluation at our centres.”
Excessive use of cleaning products like baby wipes, sugary and processed foods, and more time spent indoors are all factors which studies have linked to reduced diversity of gut bacteria and potential drivers of the rapid rise of allergies in developed countries.
A previous study by Dr Canani and colleagues found that there were significant differences in the gut bacteria of infants with and without cow’s milk allergies, which led them to test what effect transplanting bacteria might have.
Their latest work, which used samples from four healthy children and four with allergies, also looked at the bacteria that took hold in the guts of the mice and pinpointed one species, anaerostipes caccae, which appears to be behind the allergy protective effect.
Previous work has linked this species to preventing nut allergy and it produces another chemical, called butyrate, which is an essential building block for a healthy microbial community and this is now the focus of new drug developments.
“What we see with this work again 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,” said Dr Dionysios Antonopoulos, a co-author of the study from the University of Chicago.