Background and aims: The aim of our study was to investigate the influence of G-308A promoter variant in the TNF-alpha gene on insulin resistance and weight loss secondary to two hypocaloric diets.
Methods: Two hundred and three obese, nondiabetic patients were analyzed. Before and after 2 months of two hypocaloric diets, a nutritional evaluation and a blood analysis were performed. Statistical analysis was performed for the combined G308A and A-308A as mutant group and type G-308G as wild-type (WT) group.
Results: Two hundred and three patients were enrolled; 154 patients (75.5%) had the genotype G-308G and 49 patients (24.5%) had the genotype G-308A. With diet Type I and in the WT group, body mass index (BMI), weight, fat mass (FM), systolic blood pressure (SBP), diastolic blood pressure (DBP), glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) concentrations decreased. In the mutant group, BMI, weight and FM decreased. In the WT group with Type II diet, BMI, weight, FM, SBP, TC, and insulin concentrations decreased. In the mutant group, BMI, weight and FM decreased. Only leptin concentrations showed a significant decrease in the WT group with both diets (diet I: 15.6%, p <0.05 and diet II: 28.3%, p <0.05).
Conclusions: Carriers of G-308G promoter variant of TNF-alpha gene have a better metabolic response than A-308 obese patients with both diets.