Changes in diet can be effective for patients with chronic obstructive pulmonary disease (COPD), a latest research finds.

Researchers recruited around 2,200 adults with COPD to examine the effects of eating certain healthy foods. The participants were enrolled in a larger project that tracked them for three years on their dietary changes. In that study, researchers asked them on eight different occasions whether or not they ate fish, grapefruit, bananas and cheese within the past 24 hours.

The study results found that patients with COPD who consumed these four food items had fewer symptoms and better lung function performance on standard tests in comparison to COPD patients that did not make these diet changes. Furthermore, they were also found to have faster walking pace and lower levels of some markers of inflammation measured via blood samples.

"We think that diet as a whole is important," said Dr Carlos Camargo, a professor at Harvard Medical School who was not involved in the new study, according to WebMD. "A trial like that is hard to do. But it can be done."

Lead researcher Corrine Hanson, added, "Its probably the overall dietary pattern that matters. I think the take-away is that diet may be a modifiable factor for COPD patients. When we think about diet and disease, we usually think about heart disease and diabetes. But people with lung disease should be thinking about diet, too."

Hanson acknowledged the fact that they found a correlation and not a cause-and-effect relationship between these diet changes and COPD. Within the United States, COPD affects around 15 million people. The U.S. Centers for Disease Control and Prevention (CDC) reported that COPD is the nation's third leading cause of death.

The findings were presented at the American Thoracic Society's annual meeting located in San Diego, CA.