Food allergies are a constantly progressing phenomenon and remain difficult to treat. However, new therapies are coming to light with the discovery of the involvement of the microbiota.
Food allergies are a dysfunction in the immune system, which reacts abnormally immediately after ingestion of a specific food. The food, normally harmless to the body, is then called an “allergen.” These allergies affect 3% of the general population and 5% of children.
Many foods to blame
Products likely to trigger a food allergy are numerous and vary according to age and the person’s food habits. Governmental sites regularly update the list of identified allergens. Children are more sensitive to eggs, peanuts, and cow’s milk, whereas adults are more sensitive to crustaceans and mollusks, certain fruits, and soy.
In contrast with food intolerances, food allergy symptoms appear violently: they can be digestive, respiratory, or cutaneous. Angioedema, asthma attacks, and anaphylactic shock are life-threatening emergencies.
Imbalance in the microbiota
It has not yet been explained why certain foods cause an inappropriate immune reaction. Studies very quickly established a connection between these allergic phenomena and an alteration in the microbiota: allergic patients all have a different microbiota compared to healthy individuals. Observations of dysbiosis in affected people have shown that certain bacteria are responsible for the appearance of hypersensitivity to dietary proteins.
Probiotics as prevention?
Although the primary treatment for food allergies is removing the offending food, numerous studies have suggested that modulating the microbiota with probiotics and prebiotics may prevent the development of allergies.
Allergies alimentaires. Site de l'Assurance Maladie http://www.ameli-sante.fr/allergies-alimentaires/allergie-alimentaire-definition-declenchement-symptomes-et-evolution.html
Allergies alimentaires. https://www.economie.gouv.fr/dgccrf/Publications/Vie-pratique/Fiches-pratiques/Allergene-alimentaire
Thompson-Chagoyan OC, Fallani M, Maldonado J, et al. Faecal microbiota and short-chain fatty acid levels in faeces from infants with cow’s milk protein allergy. Int Arch Allergy Immunol 2011 ; 156 : 325-32
Ling Z, Li Z, Liu X, et al. Altered fecal microbiota composition associated with food allergy in infants. Appl Environ Microbiol 2014 ; 80 : 2546-54.
Barletta B, Rossi G, Schiavi E, et al. Probiotic VSL#3-induced TGF-beta ameliorates food allergy inflammation in a mouse model of peanut sensitization through the induction of regulatory T cells in the gut mucosa. Mol Nutr Food Res 2013 ; 57 : 2233-44.
Jain S, Yadav H, Sinha PR, Kapila S, Naito Y, Marotta F. Anti-allergic effects of probiotic Dahi through modulation of the gut immune system. Turk J Gastroenterol 2010 ; 21 :244-50.