According to a review of the literature published in Annals of Allergy, Asthma and Immunology.
Erin C. Davis, PhD, postdoctoral fellow in the Department of Pediatrics, Division of Allergy and Immunology at the University of Rochester School of Medicine and Dentistry and Food Allergy Center at Golisano Children’s Hospital, University of Rochester Medical Center, in Rochester, NY, based their findings on a PubMed search of English-language articles on food allergy (FA) and food sensitization (FS), prioritizing studies published after 2015.
The review explored the genetic risks of food allergy, the links between atopic dermatitis (AD) and food allergy, exposures to food allergens in early life, consumption of maternal antigens during pregnancy and l breastfeeding, breastfeeding and formula feeding, introduction to solid foods, lifestyle and environmental exposures. , gut microbiome and metabolome in food allergy and potential early immune biomarkers of food allergy.
Genetic risks for food allergy include the number of parents or siblings with a history of allergic disease, although researchers caution that part of this association may be due to the family practice of prolonged avoidance or late introduction of the allergen.
Specifically, the researchers found links between key histocompatibility complex genes, which encode the human leukocyte antigenic complex, and the development of FAs, including sensitization to peanut, cow’s milk, and egg.
The review also found that about one in three children with Alzheimer’s disease are prone to immediate type IgE-mediated FA. One hypothesis suggests that the altered skin barrier suffered by patients with AD allows epicutaneous sensitization to food prior to oral ingestion.
Noting that infants can be exposed to allergens early in life, the researchers said the mechanisms driving sensitization or tolerance likely vary depending on how that exposure occurred.
For example, according to the researchers, infants may be exposed to allergens in utero or through human milk or infant formula before they begin to eat solid foods. Environmental or household exposures to allergens are also plausible.
However, the researchers found sparse and conflicting results on the relationship between maternal consumption of allergenic foods and the risks of childhood FA, even though major food allergens were detected in amniotic fluid and breast milk. The American Academy of Pediatrics does not recommend maternal dietary restrictions to prevent atopic disease.
Studies that have assessed the protective effect of breastfeeding against FA have been mixed, the researchers continued. Breast milk includes immunomodulatory components that shape the microbiome and immune system early in life, but variations among women influence disease risk.
Early introduction of solid foods appears to have a significant impact, as the researchers cited the Learning Early About Peanut trial, which demonstrated how early and sustained peanut consumption could protect against peanut allergy. Additionally, the Inquiring About Tolerance study found a 67% lower risk of FA with early introduction when children are 1-3 years old.
The increasing adoption of a westernized lifestyle that limits less industrialized exposures to microbial influences may contribute to increased rates of FA and FS under the hygiene hypothesis, the researchers further found. .
For example, larger families are linked to a lower incidence of Alzheimer’s disease and hay fever. Exposure to pets and vaginal birth are also associated with lower risks of allergic diseases. Agricultural lifestyles can also be protective.
Such early exposures to diverse populations of microorganisms can cause the immune system to develop tolerogenic responses upon later exposures to environmental or food allergens, the researchers said.
The gut microbiome, meanwhile, is also a mediating factor in the association between increased prevalence of allergic diseases and industrialization. There may be an association between the development of FA and FS and less mature microbiomes, the researchers said, although studies have provided limited data.
Finally, the researchers found studies demonstrating associations between a differential childhood immune profile and FS and FA. Loss of immune cell populations and potential hyperreactive profiles could increase the chances of aberrant responses, including sensitization, the researchers said.
Multiple factors determine the pathogenesis of the disease, including genetics as well as maternal and infant exposure to allergens, the composition of breast milk and other environmental factors, the researchers concluded, with tolerance or sensitization likely dependent on the path of first exposures and possibly genetic risk.
Additionally, researchers have called for additional observational studies and clinical trials that span from early pregnancy through childhood so that new biomarkers and risk factors for predicting susceptibility to FS and FA can be identified. discovered.