Nutrition and allergic rhinitis: progress and perspectives on vitamin-mediated regulation.

Allergic rhinitis (AR) is a highly prevalent chronic inflammatory disease that imposes a substantial socioeconomic burden. Although conventional pharmacotherapy often provides symptomatic relief, recurrent exacerbations remain common in some patients. Micronutrients, particularly vitamins, have attracted increasing attention as potential immunomodulatory factors in AR. In this review, we identified relevant literature on vitamins, allergic airway inflammation, and immune-cell regulation from PubMed and Web of Science. Both direct evidence specific to allergic rhinitis and indirect evidence derived from asthma, broader allergic airway diseases, animal models, and in vitro cellular experiments were included, with a primary focus on distinguishing three categories of evidence: mechanistic rationale, observational associations, and clinical therapeutic efficacy. Vitamins A and D have been reported to promote regulatory T cell (Treg) differentiation and expansion while suppressing pathogenic T helper 17 (Th17) responses. Vitamin D may further stabilize mast cells, drive dendritic cells toward a tolerogenic phenotype, and enhance interleukin-10 (IL-10) production in B cells. Vitamin E and its isoforms exert anti-inflammatory effects by inhibiting mast cell activation, modulating group 2 innate lymphoid cell (ILC2) activity, and reducing Th2-type cytokine production. Extending beyond these classical immune-cell pathways, this review also discusses the potential role of vitamin-regulated microRNAs (miRNAs) in allergic inflammation. However, the strength of evidence varies substantially among vitamins. Current evidence for vitamins A, D, and E is supported by mechanistic findings, observational studies, and emerging clinical data, whereas evidence for B vitamins and vitamin C in AR remains relatively limited, inconsistent, or partly extrapolated from studies of asthma and other allergic airway diseases. Accordingly, the potential value of vitamin-based interventions should be understood within a personalized and context-dependent framework, shaped by baseline nutritional status, supplementation regimen, disease phenotype, concomitant therapy, and individual susceptibility. Further AR-specific mechanistic studies and large-scale, stratified, multicenter clinical trials are needed to clarify molecular mechanisms, validate clinical benefits, determine optimal supplementation strategies, and identify responsive populations, thereby providing a stronger evidence base for personalized nutritional approaches in the prevention and adjunctive management of AR.