The rising incidence of food allergy attracts researchers to advocate that a high-fat diet (HFD) is an attention-grabbing trigger. However, the mechanism by which HFD aggravates food allergy remains largely unknown. In this context, intestinal epithelium dysfunction as a characteristic of food allergy is summarized. Specifically, we focus our attention on the microbiota-intestinal epithelium interactions and call attention to the underlying mechanism by which HFD promotes food allergy along the interactions. Escaped fat and excessed bile acids in the colon induced by HFD can disrupt gut microbiota, directly regulating intestinal epithelium function. Additionally, HFD contributes to indirectly destroying the intestinal epithelium and enhancing its permeability by altering the level of microbial metabolites. Consequently, these ways promote the influx of food allergens. Substantial quantities of food allergens traverse the intestinal epithelium, prompting heightened secretion of pro-inflammatory cytokines, thus favoring a Th2 immune response. In this situation, impaired differentiation of Treg and Th1 cells can aggravate food allergy. Clarifying the intricate relationship between HFD and food allergy from the microbiota-intestinal epithelium interactions may offer prevention strategies for food allergy.

Gut microbiota plays an important role in food allergy. The immunoglobulin G (IgG)/immunoglobulin E (IgE) binding capacity and human gut microbiota changes of digestion products derived from glycated ovalbumin (OVA) were investigated. Gastrointestinal digestion effectively destroyed the primary structure of glycated OVA, resulting in a significantly higher digestibility than gastric digestion, and more abundant peptides < 3 kDa. Moreover, gastric and gastrointestinal digestion products have different fluorescence quenching and red shift of fluorescence peaks, and possess different conformational structures. These changes resulted in a decrease in 28.7% of the IgE binding capacity of gastrointestinal digestion products beyond that of pepsin. Moreover, gastrointestinal digestion products of glycated OVA increased significantly the proportion of Subdoligranulum, Collinsella, and Bifidobacterium. Therefore, gastrointestinal digestion products of glycated OVA altered human intestinal microbiota, reducing the risk of potential allergy.

Bovine α-lactalbumin (BLA) induced severe cow's milk allergy. In this study, a novel strategy combining ultrasonication, performed before glycation, and phosphorylation was proposed to reduce BLA allergenicity. Result showed that IgE- and IgG-binding capacities and the release rates of histamine and interleukin-6 from RBL-2H3 were reduced. Moreover, intrinsic fluorescence intensity and surface hydrophobicity were decreased, whereas glycated sites (R10, N44, K79, K108, N102 and K114) and phosphorylated sites (Y36 and S112) of BLA were increased. Minimum allergenicity was detected during BLA treatment after ultrasonic prior to glycation and subsequent phosphorylation because of considerable increase in glycated and phosphorylated sites. Therefore, the decrease in allergenicity of BLA, the effect correlated well with the shielding effect of glycated sites combined with phosphorylated sites and the conformational changes. This study provides important theoretical foundations for improving and using the ultrasonic technology combined with protein modification in allergenic protein processing.