Research appearing in Thorax (2006; 61(12): 1048-53) found that a diet rich in whole grains and fish may reduce asthma risk in children. The study involved 598 children between the ages of  8 and 13. Subjects who ate high amounts of whole grains had an odds ratio of 0.46 for current asthma and 0.28 for atopic asthma and bronchial hyperresponsiveness. Fish consumption proved even more beneficial; children with a lot of fish in their diets had an odds ration of 0..34 for current asthma and 0.12 for atopic asthma and bronchial hyperresponsiveness.

The benefit of eating fish may be due to the omega-3 fatty acids. Similarly, whole grains contain essential fatty acids not contained in refined grains. A study published in Respiratory Medicine (July 14, 2010, e-published ahead of print) compared subjects with asthma and grass pollen allergy with healthy controls. The ratio of omega-3 to omega-6 fatty acids were significantly lower in the asthmatic patients than in the healthy controls (as measured in the erythrocyte membranes). Symptoms were proportionally worse in the patients with the lowest levels of omega-3 fatty acid, with those patients exhibiting higher bronchial reactivity. This may indicate that omega-3 fatty acid supplementation may be beneficial to asthmatics.

Diet, in general, seems to have an effect on asthma. Patients with asthma should eat a diet that is high in whole grains, fish and produce. They should avoid refined foods, additives and sugar.