Dietary Nutrients in Relation to Chronic Obstructive Pulmonary Disease: Emerging Epidemiological Evidence

This article reviews the epidemiological evidence on the effects of dietary nutrients on lung function, respiratory symptoms, mortality and risk of developing chronic obstructive pulmonary disease (COPD). Published articles are located by searching several electronic databases using the relevant key words without any restriction on publication date. Article reference lists are also searched for relevant papers. A total of 23 articles are included for the present review. Intakes of antioxidants namely vitamin C, vitamin E and beta-carotene are found to be positively associated with lung function. High levels of dietary fiber appear to be beneficial to lung function while lowering the risk of COPD and respiratory symptoms. Increase intake of flavonoids may enhance lung function and reduce respiratory symptoms, but evidence in relation to COPD mortality is lacking. Recent studies also suggested that some n-3 and n-6 fatty acids may offer protection against COPD risk and mortality. For other nutrients such as vitamins A and B6, carotenoids, soy isoflavones, magnesium and selenium, limited results are available and conclusions cannot be drawn. In view of the emerging evidence, further research is required to ascertain the role of dietary nutrients on COPD.