Giving children a diet rich in fish and "fruity vegetables" can reduce asthma and allergies, according to a seven-year study of 460 Spanish children, published in the September issue of Pediatric Allergy and Immunology.
The findings also reinforce the researchers' earlier findings that a fish-rich diet in pregnancy can help to protect children from asthma and allergies.
“We believe that this is the first study that has assessed the impact of a child's diet on asthma and allergies and also taken into account the food their mother ate during pregnancy” says lead author Dr Leda Chatzi from the Department of Social Medicine at the University of Crete, Greece.
“Because we studied the children from pregnancy to childhood, we were able to include a wide range of elements in our analysis, including maternal diet during pregnancy, breastfeeding, smoking, the mother's health history, parental education and social class.”
Researchers followed the progress of the children, on the Spanish island of Menorca, at regular intervals from before they were born until they were six-and-a-half.
They discovered that children who consumed more than 40 grams of “fruity vegetables” a day – namely tomatoes, eggplants (aubergines), cucumber, green beans and zucchini (courgettes) - were much less likely to suffer from childhood asthma.
And children who consumed more than 60 grams of fish a day also suffered less childhood allergies, echoing the protective effects they experienced when their mothers ate fish during pregnancy.
However the researchers noted that the dietary effects were quite specific and that other fruits and vegetables examined did not provide the same protective effect. Nor did other food groups included in the study, such as dairy products, meat, poultry and bread.
The mothers of 232 boys and 228 girls, who had been recruited during antenatal classes, completed detailed questionnaires on their children's health, weight, diet and any breathing problems every year until their child was six-and-a-half.
90 per cent of the children also underwent allergy testing – skin prick tests were used to check their response to the six most common allergens, including grass pollen and cats.