In the largest study of its kind, researchers have determined that fruit and vegetables may be protective against asthma in both adults and children.
The systematic review and meta-analysis, published in the journal Nutrients , is the first aimed at investigating the effects of fruit and vegetable consumption on risk of asthma and wheezing, and immune responses to virus infection and inflammation, in asthma and wheezing.
Having reviewed the existing evidence, the authors reported that the majority of studies suggest a protective effect of a high fruit and vegetable diet on asthma and/or wheeze. In the meta-analysis, fruit intake was not associated with the risk of prevalent asthma, however, a negative relationship was observed between consumption of fruit and asthma severity.
Intake of vegetables was inversely associated with the prevalence of asthma, while there was no association in secondary prevention studies.
In addition, fruit intake was negatively associated with the risk of prevalent wheeze, while no significant relationship was found between vegetable consumption and wheeze prevalence. Fruit and vegetable intake together showed no significant relationship with the risk of prevalent asthma.
The researchers concluded that well-designed intervention trials are now needed to confirm the association.