22 May 2014 --- Sure, everyone knows a healthy diet provides lots of health benefits for patients with respiratory diseases, but now a new study has shown a direct link between eating fish, fruit and dairy products and improved lung function among patients with chronic obstructive pulmonary disease (COPD). Conducted by researchers in the U.S. and Europe, the study specifically looked at COPD patients' lung function within 24 hours of eating grapefruit, bananas, fish and cheese.