There has been a conspicuous increase in life-threatening food allergies in societies adopting or hosting Western-based culture. One hypothesis to explain this rising morbidity in a highly specific demographic is current lifestyle practices, such as overuse of antibiotics, has altered the human gut microbiome, the collective genome of microorganisms that live in the human gut.  Now, a study from researchers at the University of Chicago shows the gut microbiota may help to prevent the development of cow’s milk allergy. The team states their findings may help to develop microbiome-based therapies to prevent or treat food allergy.  The study is published in the journal Nature Medicine.

Previous studies show infants allergic to cow’s milk had different compositions of gut microbes than non-allergic infants. Research also revealed some microbes are associated with a lower risk of developing food allergy, leading to the theory that gut microbes of infants without milk allergy might be protective.  The current study shows germ-free mice colonized with bacteria from healthy infants tolerant to cow’s milk were protected against anaphylactic responses to a cow’s milk allergen.

The current study transplants gut microbes from eight infant donors into groups of mice sensitized to milk protein so their immune systems create antibodies to milk. Results show when exposed to milk, mice receiving no microbes from milk-allergic children produce allergic antibodies and experience anaphylaxis.  Data findings show mice receiving gut microbes from non-allergic infants had no reactions. 

Results show mice receiving microbes from non-allergic infants express different genes compared to those that did not, suggesting microbes residing in the gut impact the host’s immune system.  The group states when microbes in infant stool samples were analyzed, many differences between the stool of infants who were allergic to milk and those who were not was found. They go on to add mice transplanted with microbes from non-allergic infants threw-up one microbe, Anaerostipes caccae, isolated and shown to prevent the development of milk allergy when transplanted into mice.

The team surmises their data demonstrates the gut microbiota regulate allergic responses to dietary antigens.  For the future, the researchers state further research could lead to interventions capable of modulating bacterial communities to counteract food allergy.

Source: National Institutes of Health

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