A new study following children's diets as they grow up has found that vegetables and oily fish give protection against the development of asthma.
The study is published in the Journal of Pediatric Allergy and Immunology and was carried out by researchers at University of Crete in Heraklion, Greece.
The researchers followed 460 children for the first six and half years of their lives, monitoring their diets and recording the development of allergies. The information was gathered by periodic interviews with the children's parents.
The main findings from the study showed that allergies were less common in children who ate the most fish. In addition, asthma rates were reduced in kids who consumed a lot of vegetables, most notably tomatoes, eggplants and green beans.
To ensure the associations were as accurate as possible the research team questioned the parents about other factors known to influence the development of allergies. These factors included the mother's diet during pregnancy, duration of breastfeeding, exposure to second-hand cigarette smoke and whether there was a family history of allergies.
With all of these influences taken into account there remained a very strong association between diet and the risk of the children developing allergic diseases.
The researchers discovered that children who ate the most fish were 57% less likely to develop allergies than those who ate the least amount. The data also showed that children who ate the most tomatoes, eggplants and green beans were 62% less likely to develop symptoms of asthma compared with their peers who ate the least amount.
Oily fish such as mackeral and salmon are rich sources of the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are used by the body to make specific hormone-like chemicals called eicosanoids which are known to have strong anti-inflammatory actions and have been shown to be protective against allergies in other studies.
Vegetables such as tomatoes, eggplants and green beans are rich sources of antioxidants such as carotenoids (vitamin A), vitamin C, and lycopene. The researchers said these antioxidants may help protect lung tissue from damage, therefore protecting against the development of asthma.
The researchers concluded that certain foods are generally good for both children and adults and may offer specific protection against allergies and asthma.