Effects of dietary intervention on diet inflammatory index and asthma characteristics in obese asthmatic individuals: Randomized controlled trial

BACKGROUND AND AIM: Inflammatory factors are very important in the emergence of asthma. In recent years, the inflammatory response caused by diet has also been associated with asthma. In this study, we evaluated the association between the Dietary Inflammatory Index (DII®), weight loss, and asthma characteristics. METHODS: Obese asthmatic individuals (n = 55) were randomized into the diet (n = 29) or control groups (n = 26) for 10 weeks. The anthropometric measurements, nutrition consumption records (past 24 h), pulmonary function tests DII® were recorded and compared between groups. RESULTS: After intervention, the DII changes of the individuals in the diet group showed a negative correlation with the changes in forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), mean expiratory flow rate (MEF25–75), asthma control (ACT) and asthma quality of life questionnaire (AQLQ) scores (all P < 0.05). DII changes in the diet group showed a positive significant partial correlations (i.e. controlling for important confounders) with changes in body weight (r = 0.527; 95% confidence interval [CI]: 0.211, 0.725), FEV1, (r = −0.486; 95% CI: −0.695, −0.249), and FVC (r = −0.459; 95% CI: −0.688, −0.162). FEV1, peak expiratory flow (PEF), MEF25–75, MEF25 and ACT scores decreased with increasing DII from tertile 1 to tertile 3 (P <0.05). CONCLUSIONS: Weight loss through diet intervention and decrease in the inflammatory load of diet increase pulmonary function and improve asthma control.