Influence of Lys656Asn polymorphism of leptin receptor gene on leptin response secondary to two hypocaloric diets: A randomized clinical trial

Background: Human obesity is characterized by high levels of leptin, and it has been suggested that obese patients may be leptin-resistant. Objective: The aim of our study was to investigate the influence of Lys656Asn polymorphism in the LEPR gene on leptin response secondary to a low fat versus a low carbohydrate diet in obese patients. Design: A population of 78 obesity patients was enrolled. Before and after 2 months of two diets, a nutritional evaluation was performed. Results: 52 patients had genotype Lys656/Lys656 (wild group) and 26 patients Lys656/Asn656 or Asn656/Asn656 (mutant group). In the low fat and wild groups, BMI, weight, fat mass, glucose, total cholesterol, triglyceride, insulin, and blood pressure decreased. In mutant type (MT), BMI, weight and fat mass decreased. In wild type (WT) with low carbohydrate diet, BMI, weight, fat mass, waist circumference, waist-to-hip ratio, total cholesterol, and blood pressures decreased. In MT, BMI, weight and fat mass decreased. Only leptin concentrations have a significant decrease in WT with both diets (diet I: 30.3%; p < 0.05) and (diet II: 15.5%; p < 0.05). Conclusion: In WT patients, the changes in serum leptin concentration due to 2 months' intervention with low fat are higher than with a low carbohydrate diet. Copyright (C) 2008 S. Karger AG, Basel.