Genetic Variation in the Beta-3-adrenoreceptor Gene (trp64arg Polymorphism) and Their Influence on Anthropometric Parameters and Insulin Resistance after a High Protein/low Carbohydrate versus a Standard Hypocaloric Diet.

INTRODUCTION the Trp64Arg variant in Beta receptor has been reported to be associated with increased body weight and insulin resistance Objective: the aim of our study was to investigate the influence of polymorphism (rs 4994) in Beta-3-adrenergic receptor gene on metabolic response and weight loss in a medium-term intervention study secondary's to a high protein/low carbohydrate vs. a standard hypocaloric diets (1000 kcal/day). MATERIAL AND METHODS a population of 284 obese subjects was analyzed in a randomized trial. A nutritional evaluation was performed at the beginning and at the end of a 9-month period in which subjects received 1 of 2 diets (diet HP: high protein/low carbohydrate vs diet S: standard diet). RESULTS there were no significant differences between the positive effects (on weight, BMI, waist circumference, fat mass, systolic blood pressure and leptin levels) in either genotype group with both diets. With both diets and only in wild genotype (diet HP vs diet S), total cholesterol (-10.1 ± 3.9 mg/dl vs -10.1 ± 2.2 mg/dl;p>0.05), LDL cholesterol (-9.5 ± 2.1 mg/dl vs -8.5 ± 2.3 mg/dl;p>0.05) and triglycerides (-19.1 ± 2.1 mg/dl vs -14.3 ± 2.1 mg/dl;p>0.05) decreased. The improvement in these parameters was similar in subjects with diet HP than HS. With diet HP and only in wild genotype, insulin levels (-3.7 ± 1.9 UI/L;p<0.05) and HOMA-R (-0.7 ± 0.1 units;p<0.05) decreased. CONCLUSION metabolic effect of weight reduction by two hypocaloric diets is the greatest in subjects with normal homozygous beta 3-AR gene. Improvement in total cholesterol, LDL-cholesterol, triglyceride, glucose, insulin and HOMA-R levels is better than in the heterozygous group.