Will eating more fish relieve my asthma symptoms?

Some of the most important mediators of allergic activity, notably prostaglandins and leukotrienes, are intermediate and end products of fatty acid metabolism. Research into the effects of leukotrienes has spurred the development of new drugs to block their activity, and appear to be of benefit in some asthma patients, particularly those with more severe disease.

When cold-water fatty fish containing relatively large amounts of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are eaten, or when their oil is taken as a supplement, EPA and DHA displace arachidonic acid from cell membranes. These cells subsequently release relatively higher concentrations of fish-derived oils. The end products are mediators that are less inflammatory than normal. This shift toward less inflammatory mediators would lead us to expect to see less inflammatory activity in the lungs, and a subsequent improvement in asthma symptoms. Epidemiological studies do show that the more fish we eat, the less risk of asthma. However, the clinical data is equivocal when it comes to taking omega-3 fatty acid supplements, with studies showing both positive and negative results.