Fruit and vegetable consumption in relation to allergy: disease-related modification of consumption?

BACKGROUND: Previous largely cross-sectional studies suggest that fruit and vegetable consumption reduces the risk of allergic disease in children, but results are conflicting.
OBJECTIVE: To investigate the association between current fruit or vegetable intake and allergic disease in 8-year-old Swedish children, and to evaluate the potential effect of disease-related modification of consumption.
METHODS: Cross-sectional data were obtained from a Swedish birth cohort study. Information on fruit and vegetable consumption as well as symptoms and diagnoses of allergic diseases was obtained by parental questionnaires at the 8-year follow-up. Allergen-specific IgE levels against food and inhalant allergens were obtained from blood samples collected at age 8 years. In total, 2447 children were included. Data were analyzed with logistic regression.
RESULTS: An inverse relation was observed between total fruit consumption and rhinitis (odds ratio, highest vs lowest quartile, 0.62; 95% CI, 0.45-0.86; P for trend, .002), whereas no association was observed for total vegetable intake. In analyses of individual foods, intake of apples/pears and carrots was inversely associated with rhinitis, asthma, and atopic sensitization. Fifty percent of the children with rhinitis were sensitized against birch pollen, which may cross-react with apples and carrots. After exclusion of children who reported food-related allergic symptoms, most of the observed inverse associations moved toward the null and became nonsignificant.
CONCLUSION: We confirm the inverse associations between fruit intake and allergic disease in children observed in earlier studies. However, our data also indicate that disease-related modification of consumption contributed to this association.