Dietary factors for chronic obstructive pulmonary disease: epidemiological evidence

Chronic obstructive pulmonary disease (COPD) is the fifth most common cause of morbidity and the sixth leading cause of death worldwide. While 95% of patients with COPD are, or have been, cigarette smokers, only 20% of smokers develop COPD. Therefore, other factors, such as dietary and environmental exposures, may protect against or contribute to the development of the disease. An extensive literature review suggested that fruit intake is positively associated with lung function and inversely related to COPD mortality and respiratory symptoms. Increased vegetable consumption also reduces the risk of COPD, while a high fish intake is beneficial to lung function. High levels of meat consumption, however, may increase COPD risk and respiratory symptoms, and can lead to a decline in lung function, whereas the effect of wholegrain is inconsistent. Further research is required to ascertain the role of dietary factors in view of the emerging evidence from epidemiological studies.