Among elderly men with chronic obstructive pulmonary disease (COPD), proper intake of fiber, protein, carbohydrate, vitamin C, niacin, and riboflavin was associated with less severe airway impairment, according to a study recently published in COPD.
This study included 702 participants (n=418 men; n=284 women) with COPD from the sixth Korea National Health and Nutrition Examination Survey (KNHANES). Participants were stratified by airflow limitation as determined by predicted forced expiratory volume in 1 second (FEV₁): mild (FEV₁≥80%), moderate (50%≤FEV₁<80%), and severe (30%≤FEV₁<50%), and very severe (FEV₁<30%). Metrics were also collected on participants’ smoking status, anthropometric measures, socioeconomic factors, and nutrient intake. To evaluate the dose-dependent relationship between nutrient intake and COPD severity, researchers used the Jonckheere-Terpstra test. The association between nutrient intake and predicted FEV₁ was examined using multivariate analysis, with age, height, sex, smoking status, educational level, residential area, and household income as covariates.
Among all men, disease severity showed a significant decrease with increased intake of vitamin A (P =.019), retinol (P =.043), beta-carotene (P =.039), thiamin (P =.009), and riboflavin (P =.004). In a fully adjusted model, vitamin A was the only nutrient showing a positive association with percentage FEV₁ (P =.034) in men. Among elderly men, disease severity was significantly lower with increased intake of carbohydrate (P <.001), fiber (P =.006), protein (P =.020), thiamin (P =.002), riboflavin (P =.018), niacin (P =.008), and vitamin C (P =.021). None of these associations reached statistical significance in women.
Limitations to this study included a lack of causal inferences, the lack of postbronchodilator response test in the KNHANES, the dependence on participant memory in the 24-hour dietary recall method, and potential selection bias.
The researchers concluded that “[c]arbohydrate, protein, fiber, vitamin A, thiamin, riboflavin, niacin, and vitamin C intake were associated with decreased airway impairment severity in COPD patients.” Furthermore, this correlation “was more prominent in elderly patients” and underscores “the importance of appropriate nutrient intake in relieving airway inflammation and supporting energy production.”
Kim T, Choi H, Kim J. Association between dietary nutrient intake and chronic obstructive pulmonary disease severity: a nationwide population-based representative sample [published online December 13, 2019]. COPD. doi:10.1080/15412555.2019.1698530