Breastfeeding could promote the transmission of dust mite allergens and the onset of asthma and rhinitis in children, according to a study.
Breast milk, beneficial… But to what extent? A study by Inserm, published in the journal Journal of Allergy and Clinical Immunology, points to an unexpected risk associated with breastfeeding: the transmission of sensitivity to dust mites, the cause of childhood allergies.
The work, carried out using data from the EDEN cohort, shows that dust mite allergens could be present in the milk of breastfeeding mothers and promote the onset of asthma or allergic rhinitis in their children.
Oral sensitization
“In this study, conducted in 255 women, we looked for the presence and measured Der p1, explains Isabella Annesi-Maesano, who led the study, quoted in a communicated from Inserm. It is an allergen from the main house dust mite Dermatophagoides pteronyssinus she describes.
According to the team’s observations, the milk of two-thirds of the mothers included in the cohort did contain Der p1, in amounts similar to those usually found in breast milk for the most common food allergens.
The researchers then assessed the incidence of asthma or allergic rhinitis in their children. “At the age of five, children born to mothers with an allergic background and a high level of allergens in their milk suffered more often from asthma and rhinitis than the others. This tends to prove that respiratory allergens could not only sensitize children through the air, but also orally,” concludes the researcher.
The protective effect in question
This observation raises questions about the reputed protection of breast milk against allergies: “This study confirms that this protective effect is not sufficient to prevent all allergies. Our conclusion is surprising, especially since other work has shown that food allergens present in milk reduce the risk of food allergy in children.
This apparent contradiction could be linked to the way the allergen is processed by the infant’s immune system, or to the presence of other compounds from house dust mites in the milk.
The work still needs to be confirmed by larger studies, currently underway, explains Inserm. “This will allow, thanks to data from different regions of the globe, to confirm the universality of these first data”.
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