How could diet affect respiratory diseases?

Diet appears to play a role in the development, severity, and management of some respiratory diseases, especially when atopy (immune response) and airway inflammation are important factors (as is the case in COPD and asthma). Diet-related evidence is primarily sourced from epidemiological and some preclinical animal studies, but experimental human evidence is lacking. In general, high fruit and vegetable intake, a Mediterranean diet, and omega-3 fatty acid intake have shown benefits in respiratory diseases, whereas Western diets and fast food diets have shown adverse associations. ^[1]