Effect of Dietary Supplements With Fish Oil on Mannitol-induced Airway Sensitivity & Inflammation in Persons With Asthma

We wish to investigate the effects of 3 weeks of orally administered fish oil supplements on the airway sensitivity (provoking dose to cause a 15% fall in FEV1, PD15) to inhaled mannitol (AridolTM). Mannitol, an osmotic stimulus has been demonstrated as a useful model for exercise-induced asthma. We also wish to investigate if there is any associated improvement associated with selected markers of airway inflammation that can be measured in the sputum, blood, urine and exhaled breath condensate. Oral fish oil supplements have recently been demonstrated to be effective inhibitors of exercise-induced asthma, in association with an inhibition of markers of inflammation, over a 3 week treatment period. This finding has important implications in the treatment of asthma as this is a faster and more effective improvement than what is seen with inhaled corticosteroids on exercise-induced asthma. This observation requires validation and further investigation. We wish to study this in two patient groups; (a) steroid naïve asthmatics taking beta2 agonist when required and (b) asthmatics taking regular inhaled corticosteroids \< 1000 mcg/day.