The natural substances with anti-allergic properties in food allergy

Food allergy (FA) is an immune system reaction that occurs soon after eating certain food, which severely damages the health of allergic patients. Since medical approaches for FA may trigger severe adverse effects, the natural substances with anti-allergy functions have received more and more attention. This paper reviewed the natural bioactive substances with anti-allergic properties in food allergy, which mainly include polyphenols, polysaccharides, oligosaccharides, traditional Chinese medicine (TCM) and probiotics. Moreover, this paper analyzed the limitations of current investigations and provided future outlook for the development of anti-allergic products. This paper extensively reviews the natural substances with anti-allergy functions. As the results, the polyphenols could inhibit the formation of allergen-IgE complex, influence the allergen-IgE complex bind to the receptor (FcϵRI) on the surface of effector cells (e.g. mast cells and basophils). The polysaccharides and oligosaccharides could inhibit the secretion of allergic mediators and cytokines, suppressing Th2 responses and promoting Th1/Treg responses. The TCM could reduce allergen presentation to dendritic cell, weaken the secretion of allergen-specific IgE and the degranulation of mast cell, upregulate Th1 cytokines (e.g. IL-12, IFN-γ) and downregulate Th2 cytokines (e.g. IL-4, IL-13). The probiotics could help maintain the integrity of intestinal epithelial barriers by promoting mucus production via goblet cells, which could reduce the intestinal permeability and improved mucus generation to decrease the risk of food allergen into immune systems. This review could provide a better understanding and future outlook on the natural anti-allergy substances and supply a novel insight into their potential application for FA prevention and treatment.