Food allergy, characterized by a reproducible adverse reaction to a specific food mediated by IgE, has become a global concern due to its increasing prevalence and severity in the last decade. Survey data in the United States shows that approximately 7.6% of children suffer from food allergies, with an 18% increase in prevalence from 1997 to 2007 [1,2]. Moreover, hospitalization rates for food allergies have increased in young children, with an annual increase of 6.6% from 1998 to 2018 in the United Kingdom [3]. Recently, Chinese scholars reported that the prevalence of food allergies among Chongqing children increased from 3.5% to 11.1% between 1999 and 2019 [4]. Although genetic studies have shown that hundreds of genes are associated with IgE-mediated food allergies. The occurrence of food allergies would be reinforced by the interaction between genes and the environment, which can affect the expression of genes related to the immunopathology of the disease [5]. While the environmental factors including nutrition [6], microbiota [7], pollution [8], and smoking [9] that contribute to the risk of food allergies have been well characterized, the underlying mechanisms behind these associations are still unclear. Environment-driven epigenetic modifications provide a potential molecular basis for food allergies, as these modifications can alter the expression of genes involved in the immune signaling pathway [10].

Epigenetic biomarkers are mitotically and/or meiotically heritable but reversible biochemical modifications of the chromatin that carry information without changing genome's nucleotide sequence. This concept first proposed by Waddington in 1942, explores the impact of epigenetic modifications on gene expression, leading to changes in phenotype. Epigenetics has since been recognized as playing a role in various biological processes including embryonic development. Growing evidence confirms the importance of epigenetics in immune regulation and complex human diseases, such as cancer. Currently, the significance of epigenetics in the field of food allergies has increased. Previous studies primarily focused on investigating blood epigenetic biomarkers, particularly DNA methylation (DNAm) and microRNAs, have been found associations with food allergies [11], [12], [13]. Available data also suggest that epigenetic regulation plays a crucial role in influencing immune cell function [14], [15], [16]. Obviously, the unique epigenetic changes observed in food-allergic patients contribute to the functional regulation of immune cells during allergic reactions. Additionally, diet components have been attributed important role in immunomodulatory. Further details on all of these aspects will be provided in the following section.