Healthy diet counteracts air pollution effects in asthmatic children
MedWire News: A diet rich in fruits and vegetables and adhering closely to the Mediterranean diet helps protect the lung health of asthmatic children exposed to air pollution, research shows.
Reporting their findings in the journal Respiratory Research, Isabelle Romieu (Instituto Nacional de Salud Pública, Cuernavaca, Mexico) and colleagues suggest that a healthy diet "should be promoted to counteract environmental insults in asthmatic children."
Exposure to air pollution has previously been linked to lung function impairments and an increase in respiratory symptoms, with asthmatic children particularly vulnerable.
Fruits and vegetables are rich in antioxidants, and studies have shown that antioxidant supplementation modulates the adverse effects of ozone (O3) on lung function and inflammatory responses.
The Mediterranean diet has also been shown to have antioxidant potential, and to have a beneficial effect on rhinitis and asthma in children and lung function in adults.
In this study, researchers studied 158 asthmatic children aged six to 14 years old living in Mexico City between 2003 and 2005. Fifty non-asthmatic children served as controls.
Dietary intake was assessed using a detailed food frequency questionnaire and from this two indices, the fruit and vegetable index (FVI) and Mediterranean diet index (MDI), were constructed.
The FVI was inversely related to interleukin-8 (IL-8) levels. For each 1-unit increase in FVI there was a significant decrease in IL-8, with children with the greatest intake of fruits and vegetables having 8% lower IL-8 levels than children with the lowest intake.
The MDI was positively related to lung function, with children adhering closest to the diet having a higher FEV1 and forced vital capacity than children with the poorest adherence.
A significant interaction of FVI and MDI with O3 exposure on IL-8 and lung function was also observed. The findings suggest that "high intake of fruits and vegetables and close adherence to the Mediterranean diet could modulate the adverse effect of O3," according to the researchers.
No effect of diet was observed among healthy children.
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