a1 GSF – National Research Center for Environment and Health, Institute of Epidemiology, PO Box 1129, D-85758, Neuherberg, Germany
a2 Ludwig-Maximilians University of Munich, Institute of Medical Data Management, Biometrics and Epidemiology, Munich, Germany
a3 Department of Food and Nutrition, TU Munich, Munich, Germany
a4 Unit of Human Nutrition and Cancer Prevention, TU Munich, Munich, Germany
a5 Division of Clinical Epidemiology, German Cancer Research Centre, Heidelberg, Germany
Objectives Antioxidant nutrients like carotenoids, tocopherols and vitamin C have been suggested to protect against allergic rhinitis and allergic sensitisation but scientific evidence is scarce. The aims of the study were to measure the plasma concentration of six carotenoids, α- and γ-tocopherol and vitamin C as biomarkers of the intake, absorption and subsequent metabolism of these nutrients, and to assess their association with allergic rhinitis and sensitisation.
Method Data from a cross-sectional study on representative dietary and lifestyle habits of the population of Bavaria, Germany, were analysed. The plasma levels of six carotenoids (α-carotene, β-carotene, lycopene, lutein/zeaxanthin, canthaxanthin and cryptoxanthin) as well as of α-tocopherol, γ-tocopherol and vitamin C were measured in 547 adults aged between 19 and 81 years. Participants with specific serum immunoglobulin E ≥700 U l−1 were categorised as sensitised. The association of plasma antioxidant levels, allergic rhinitis and allergic sensitisation was assessed by means of unconditional logistic regression models.
Results We observed a negative association between plasma total carotenoids and the prevalence of allergic rhinitis, with odds ratio (95% confidence interval) of 1.13 (0.54–2.39) for the second, 0.72 (0.33–1.58) for the third and 0.44 (0.19–1.03) for the fourth quartile of total carotenoids concentration (P for trend = 0.0332); results for lycopene failed to reach statistical significance (P = 0.0608). Other single carotenoids, tocopherols and vitamin C were unrelated to allergic rhinitis. Allergic sensitisation was negatively associated with plasma γ-tocopherol, with odds ratio (95% confidence interval) of 0.92 (0.51–1.65) for the second, 1.00 (0.56–1.80) for the third and 0.45 (0.23–0.88) for the fourth quartile of plasma γ-tocopherol concentration (P for trend = 0.0410). No other antioxidant was significantly related to allergic sensitisation.
Conclusions High plasma carotenoid concentrations reflecting a diet high in various fruits and vegetables might have a protective effect on allergic rhinitis in adulthood.
(Received August 28 2005)
(Accepted August 23 2005)