Background: Although many studies have reported the effects of dietary vitamin E on the immune response, none so far has assessed its role in nasal allergy.
Methods: Female BALB/c mice were randomized into two groups and fed a 20% casein diet (control group, 50 mg vitamin E/kg diet) or this diet supplemented with 535 mg vitamin E/kg diet (vitamin E group, 585 mg vitamin E/kg diet) for 4 weeks. During the fifth week, the mice in each group were divided into two subgroups to form a total of four treatment groups: group A (control), group B [control + toluene diisocyanate (TDI) sensitization], group C (vitamin E supplementation), and group D (vitamin E supplementation + TDI sensitization). Groups B and D were treated with two courses of intranasal application of 5% TDI in ethyl acetate, whereas groups A and C were treated with ethyl acetate alone. A week after second sensitization all groups were provoked by applying 2.5% of TDI in the vehicle and nasal allergic responses were observed for 10 minutes. Splenic lymphoproliferation, splenic cell cytokines, and the total serum IgE were measured.
Results: Members of group D had lower (P < 0.01) scores of nasal response and sneezed less frequently (P < 0.01) than those of group B. Similarly, splenic lymphoproliferation and production of IL-4 and IL-5 as well as the total serum IgE levels were lower (P < 0.01) in group D than in group B.
Conclusions: The results indicate that higher doses of vitamin E supplementation may suppress nasal allergic responses.