Diet Protecting Against Childhood Asthma-Like Symptoms and Rhinitis

April 9, 2007 — Greek children who had a high intake of fruits, vegetables, and nuts and adhered to a traditional Mediterranean diet were protected against asthma-like symptoms and rhinitis, according to the results of a cross-sectional survey reported in the April 5 Online First issue of Thorax.

"Atopy is not uncommon among children living in rural Crete, but wheeze and rhinitis are rare," write Leda Chatzi, MD, from the University of Crete in Heraklion, Greece, and colleagues. "A study was undertaken to examine whether this discrepancy could be attributed to a high consumption of fresh fruit and vegetables or adherence to a traditional Mediterranean diet.... Suboptimal dietary intake of antioxidant vitamins, especially vitamins A, C, and E and the carotenoids, as well as other antioxidants such as selenium and flavonoids may have an adverse effect on the modulation of oxidative lung stimuli; higher intakes may have beneficial associations with asthma, wheezing symptoms and ventilatory function."

Parents of 690 children aged 7 to 18 years in rural Crete completed a questionnaire about their child's respiratory and allergic symptoms and a 58-item food frequency questionnaire. A scale with 12 dietary items measured adherence to a Mediterranean diet. Children underwent skin prick tests with 10 common aeroallergens.

Two servings or more daily of fresh fruit and of vegetables were consumed by 80% of children and 68% of children, respectively. Intake of grapes, oranges, apples, and fresh tomatoes (the main local produce in Crete) was not associated with atopy but was protective against wheezing and rhinitis.

High nut consumption was inversely associated with wheezing (odds ratio [OR], 0.46; 95% confidence interval [CI], 0.20 - 0.98). However, margarine was associated with increased risk for both wheezing (OR, 2.19; 95% CI, 1.01 - 4.82) and allergic rhinitis (OR, 2.10; 95% CI, 1.31 - 3.37). A high level of adherence to a Mediterranean diet was protective for allergic rhinitis (OR, 0.34; 95% CI, 0.18 - 0.64), whereas protection was more modest against wheezing and atopy.

Study limitations include absence of information on the consumption of "fast foods," sweets, and legumes; cross-sectional design; inability to determine causal relationships; different etiologies of wheezing; lack of data on parental atopy; self-administered questionnaire; and lack of validation of the food frequency questionnaire in this population.

"The results of this study suggest a beneficial effect of commonly consumed fruits, vegetables and nuts, and of a high adherence to a traditional Mediterranean diet during childhood on symptoms of asthma and rhinitis," the authors write. "Diet may explain the relative lack of allergic symptoms in this population."

Medicor and the Fifth Framework of the European Community supported this study. The authors have disclosed no relevant financial relationships.

Thorax. Published online April 5, 2007.

Source: http://www.medscape.com/viewarticle/554819?src=mp