Eating a Mediterranean diet could help protect children from respiratory allergies and asthma, a study suggests.
Fruit consumption was monitored as part of the study
UK, Greek and Spanish researchers assessed the diet and health of almost 700 children living in rural areas of Crete, where such conditions are rare.
They found those with a diet rich in fruit and vegetables were protected against both conditions.
UK experts said the study, in Thorax, added to existing evidence that diet could help control asthma symptoms.
More than five million people in the UK currently have asthma, and one in 10 children is affected.
The research was carried out by experts from the UK's National Heart and Lung Institute, the University of Crete, Venezelio General Hospital, in Crete, and the Centre for Research in Environmental Epidemiology, in Barcelona.
The team wanted to examine why children in some parts of Europe, such as the UK, get asthma while others, in places like Crete, do not.
They looked at the incidence of asthma symptoms, such as wheezing, and of allergic rhinitis, caused by dust mite or pet allergies.
Parents of the children, who were aged between seven and 18, were also asked how often they ate 58 foods in nine categories; vegetables, fruits, nuts, fish, cereal, dairy products, meat, poultry and margarines and oils.
The Mediterranean diet is rich in vegetables and fruit and low in saturated fats.
Skin allergies are relatively common in Crete - meaning that, in tests, children react to allergens such as dust mites.
But these do not appear to translate into respiratory allergies, such as asthma and allergic rhinitis.
The research found 80% of the children ate fresh fruit, and over two-thirds of them fresh vegetables, at least twice a day.
Eating oranges, apples, tomatoes and grapes each day, which around 300 children did, was shown to have a protective effect against wheezing and allergic rhinitis.
Red grape skin contains high levels of antioxidants as well as resveratrol, a potent polyphenol, known to curb inflammatory activity, say the authors.
Children who ate nuts - a rich source of vitamin E - at least three times a week, again just over 300, were less likely to wheeze.
Vitamin E is the body's main defence against cell damage caused by free radicals.
Nuts also contain high levels of magnesium, which other research has suggested may protect against asthma and boost lung power.
However, high consumption of margarine more than once a week (331 children) doubled the chances of asthma and allergic rhinitis, compared with those who ate it less frequently, the findings showed.
Dr Paul Cullinan, of the Royal Brompton Hospital and National Heart and Lung Institute, said: "It may be that diet is an important link in translating skin test responses to actual allergies.
"The message of the study is that foods with high antioxidant levels are good for you."
Leanne Male, assistant director of research at Asthma UK said: "The results of this study add to the existing evidence which indicates that a healthy diet can play an important role in the control of asthma symptoms.
"They demonstrate that the Mediterranean diet, which traditionally contains higher levels of fresh fruit and vegetables, can have a beneficial effect on asthma symptoms in children.
"This benefit is thought to be linked to the vitamins and antioxidants which they contain and Asthma UK is currently funding a number of research projects to further explore this association."