“Food Is Medicine” Strategies for Respiratory Health: Evidence From NHANES 2005–2012

Compared with other diseases with similar global burdens, little is known about how lifestyle factors other than smoking affect respiratory health, and few studies have systematically investigated the combined associations between diet and respiratory health. The aim of this research was to examine the Dietary Inflammation Index (DII), Healthy Eating Index (HEI)-2015, and individual food and nutrient associations with multiple respiratory outcomes. This study combined a cross-sectional study with a prospective cohort study to systematically evaluate data from adults aged 40 years or older (N = 13,227) from 4 National Health and Nutrition Examination Survey cycles (2005-2006 through 2011-2012) with lung function measures in a subset (n = 6337). DII, HEI-2015, and individual foods and nutrients were evaluated for their associations with respiratory symptoms (cough, phlegm problem, wheezing, and exertional dyspnea), chronic lung disease (asthma, chronic bronchitis, and emphysema), lung function (percentage of predicted forced expiratory volume in 1 second [FEV1pp], percentage of predicted forced vital capacity [FVCpp], forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC), obstructive or restrictive spirometry patterns), respiratory cancer, all-cause mortality, and respiratory disease mortality. For each point increase in DII, the odds of cough (adjusted odds ratio [aOR], 1.036; 95% CI, 1.002-1.071), wheezing (aOR, 1.044; 95% CI, 1.013-1.075), exertional dyspnea (aOR, 1.042; 95% CI, 1.019-1.066), emphysema (aOR, 1.096; 95% CI, 1.030-1.166), and restrictive spirometry patterns (aOR, 1.066; 95% CI, 1.007-1.128) increased and FEV1pp (adjusted mean difference [aMD], -0.525%; 95% CI, -0.747% to -0.303%) and FVCpp (aMD, -0.566%; 95% CI, -0.762% to -0.371%) decreased. HEI-2015 scores were similarly associated with these respiratory outcomes. Each point increase in the DII was associated with an increased risk of all-cause mortality (adjusted hazard ratio [aHR], 1.048; 95% CI, 1.025-1.071) and respiratory disease mortality (aHR, 1.097; 95% CI, 1.013-1.189); each increase in the HEI-2015 score was associated with a decreased risk of all-cause mortality (aHR, 0.994; 95% CI, 0.991-0.997). The multiple adequacy components recommended in the HEI (fruits, vegetables, whole grains, seafood and plant proteins, and monounsaturated fatty acids) were associated with better respiratory outcomes; the moderation components of restricting refined grains, sugars, and saturated fats were associated with better respiratory outcomes, but restricting sodium intake was associated with increased respiratory symptoms. The results of this study suggest that a low-inflammatory diet and a healthy diet are consistently associated with better respiratory outcomes. These findings support the potential benefits of a "Food Is Medicine" strategy for respiratory health.