Comparing effects of low glycemic index/high-fat, high-calorie diet and high-fat, high-calorie diet on cytokine levels of patients with cystic fibrosis: A randomized controlled clinical trial.

The importance of the host inflammatory response, as a central pathological feature of cystic fibrosis, is well recognized. Additionally, hyperglycemia can induce an immune response and consecutively may exacerbate symptoms of this disease. Hence, adherence to a low glycemic index diet, through normalizing blood glucose levels, may reduce inflammation in patients with this disease. This study aimed to compare effects of a low glycemic index/high-fat, high-calorie diet and routine high-fat, high-calorie diet on inflammatory biomarkers in patients with cystic fibrosis. In this randomized clinical trial, 44 children and adolescents with cystic fibrosis were randomly assigned to receive for three months either a high-fat, high-calorie diet (n = 22) or a low glycemic index/high-fat, high-calorie diet (n = 22) with similar calorie and macronutrients composition to the control diet. Patients in first arm were allowed to use all sources of carbohydrates with different glycemic indices, whereas those in another arm consumed carbohydrates from low glycemic index sources. Serum levels of the pro-inflammatory cytokines IL-6, IL-17A, and IFNγ, and the anti-inflammatory cytokine IL-10 were measured at baseline and after the end of the trial. There were significant differences between groups for IL-6 (P = 0.02) and IL-17 (P = 0.01), in favor of the low glycemic diet, but no between-group differences were detected in IL-10 and IFN-γ. Although serum levels of IL-17 were reduced in both the groups as compared with the baseline values, this reduction was only significant in the group assigned to the low glycemic diet (P= 0.007), In addition, IL-6 serum levels decreased and those of IL-10 increased significantly as compared with the baseline values in the low glycemic diet (P= 0.01). It seems that adherence to a low glycemic index/high-fat, high-calorie diet for three months can improve some inflammatory biomarkers in children and adolescents with cystic fibrosis compared with the high-fat, high-calorie diet.

Effects of low glycemic index/high-fat, high-calorie diet on glycemic control and lipid profiles of children and adolescence with cystic fibrosis: A randomized double-blind controlled clinical trial.

PURPOSE: Low glycemic index diets seem to be potentially effective to improve glycemic control and reduce lipid profiles. Hence, this study aimed to evaluate the effect of a low glycemic index/high fat, high-calorie diet on glycemic status and lipid profiles of patients with cystic fibrosis. METHODS: In this randomized clinical trial, 44 children and adolescents with cystic fibrosis were randomized to receive for three months either a high fat, high-calorie diet (n = 22) or a low glycemic index/high fat, high-calorie diet (n = 22) with similar calorie and macronutrients composition. Patients in high fat, high-calorie diet arm were allowed to use all sources of carbohydrates with different glycaemic indices; whereas those in another arm consumed carbohydrates from low glycemic index sources. Serum levels of lipid profiles (triglyceride, total cholesterol, HDL cholesterol, LDL cholesterol), insulin, fasting blood glucose, and glycated hemoglobin were measured at baseline and after the intervention. RESULTS: Between-group differences were significant only for fasting blood glucose (P < 0.001). However, fasting blood glucose (P = 0.003) and glycated hemoglobin (P = 0.002) significantly decreased after the intervention in the low glycemic index group, while in another group a significant increase in fasting blood glucose (P = 0.038) and triglyceride (P = 0.004) was found. No significant within-group differences were observed in other variables in both groups. CONCLUSIONS: It seems that adherence to a low glycemic index/high fat, high-calorie diet can improve glycemic indices in children and adolescents with cystic fibrosis compared to the high fat, high-calorie diet. TRIAL REGISTRATION: IRCT2017102325267N5.