# Sustainable Plant-Based Diets and Food Allergies: A Scoping Review Inspired by EAT-Lancet
## 4 Discussion  
This review highlights how sustainable plant-based dietary patterns--particularly those aligned with the EAT-Lancet and Mediterranean frameworks--may act as both preventive and therapeutic tools in the context of food allergies, through mechanisms that extend beyond allergen exclusion. Within this context, plant-based diets represent a valuable adjunct due to three key features: (1) the reduction or elimination of common allergenic foods such as dairy, eggs, and shellfish; (2) the enhancement of gut microbial health through increased intake of fermentable fibers, fruct-oligosaccharides (FOSs), and microbiota-derived short-chain fatty acids (SCFAs); and (3) the anti-inflammatory and immunomodulatory effects of polyphenols found in whole plant foods. Among the most extensively supported factors, gut microbiota modulation, polyphenol intake, fiber-induced SCFA production, and probiotic supplementation emerge as key drivers of immune resilience. Microbiota-targeted strategies appear central to both allergy prevention and symptom modulation. Fermentable fibers present in legumes, fruits, and whole grains are metabolized by commensal bacteria into short-chain fatty acids (SCFAs), notably butyrate and propionate, which interact with G-protein-coupled receptors such as GPR43 and GPR109A on intestinal epithelial and immune cells. These SCFAs inhibit histone deacetylases (HDACs), promote Treg cell differentiation, enhance IgA secretion, and strengthen the intestinal barrier by upregulating tight-junction proteins including occludin and claud-1 [4; 7; 19]. SCFAs also suppress the Th2 cytokine axis and reduce eosinophilic infiltration in allergic tissue models [20]. Polyphenols act synergistically on immune and epithelial compartments. In in vitro studies, flavonoids such as quercetin, epigallocatechin gallate, and resveratrol have demonstrated mast cell stabilization, suppression of IL-4,IL-5, and IL-13, and inhibition of NF-\(\kappa\)B and GATA-3 signaling [8; 30; 31]. These effects are mediated in part via modulation of Toll-like receptors (TLRs), inhibition of oxidative stress, and direct binding to allergenic epitopes, although these findings are primarily supported by preclinical and in vitro studies [10; 29] Conjugation of polyphenols to food proteins also alters tertiary structure and masks conformational IgE-binding domains, decreasing antigenicity [8; 29]. Probiotic supplementation during pregnancy or infancy, particularly with Lactobacillus and Bifidobacterium strains, has been associated with lower food allergy incidence in offspring. Meta-analytic data confirm that antenatal probiotic use increases microbial \(\alpha\)-diversity and SCFA production, facilitating the development of oral tolerance [9; 38]. Mechanistically, probiotics reduce Th2 polarization, promote IL-10 and TGF-\(\beta\) production, and enhance mucosal IgA responses [33; 35]. Dietary diversity--especially when derived from seasonal, minimally processed plant foods--supports immunotolerance via microbial and antigenic variety. High plant-food diversity increases microbial richness and functional redundancy, enhances SCFA biosynthesis, and favors microbial communities enriched in _Faecalibacterium prausnitzii_ and Bifidobacterium species, which are associated with decreased allergic sensitization [4; 5; 10]. While the aforementioned points represent core factors supported by robust data, several adjunctive elements warrant further attention. Food processing methods, for example, can either reduce or enhance allergenicity. Enzymatic hydrolysis and microbial fermentation of soy, legumes, and nuts reduce IgE-binding capacity and mast cell degranulation, in part by modifying protein conformation and reducing the stability of immunogenic epitopes [21; 23; 24]. In contrast, Maillard reactions may stabilize allergenic domains, increase resistance to digestion, and enhance antigen presentation by dendritic cells [7; 22].