Are cow’s milk allergy and gut microbiota related?
Could we prevent and/or cure cow's milk protein allergy by restoring the microbiota of at-risk children? This hypothesis seems to be confirmed by studies published in the Nature Medicine journal.
Cow's milk protein allergy affects a lot of newborns fed with infant formula. It appears as varying gastrointestinal (abdominal pains, diarrhea, vomiting), respiratory (cough, sneezing) and skin (hives, eczema) symptoms, that are more or less specific. Impairment of the gut microbiota due to the increase of C-sections and the decrease in breastfeeding could explain this spreading phenomenon.
The microbiota into question
After observing that the microbiota composition of children allergic to cow’s milk is very different to that of non-allergic children, an American team partnered with researchers from Naples, Italy, to investigate the role of commensal bacterial (naturally present in the intestines) in preventing food allergies. They transplanted either the microbiota of allergic or healthy newborns to germ-free mice. When exposed to cow's milk allergen (beta-lactoglobulin), rodents from the first group all developed an anaphylactic reaction (severe and widespread allergic reaction), while those from the second group did not experience any symptom.
A protective species has been identified
Based on their research, they identified the bacterial species that seems to be associated to a lower risk of allergic reaction: Anaerostipes caccae, a butyrate-producing molecule that ensures good intestinal health. Nevertheless, based on their data it is not clear whether the imbalance of the microbiota composition (“dysbiosis”) is a cause or a consequence of cow’s milk allergy. The results showed that commensal bacteria played a major role in the prevention of food allergies, or at least cow’s milk allergy, and confirm the benefits of developing innovative strategies based on microbiota modulation to prevent and/or treat these diseases.
Feehley T, Plunkett C, Bao R et al. Healthy infants harbor intestinal bacteria that protect against food allergy. Nature Medicine, Letters https://doi.org/10.1038/s41591-018-0324-z