POLYMORPHISMS OF UNCOUPLING PROTEIN (UCP) AND BETA-3 ADRENOCEPTOR GENES IN OBESE PEOPLE SUBMITTED TO A LOW-CALORIE DIET

OBJECTIVE: To investigate whether the genetic polymorphisms of the unc oupling protein (UCP) and beta 3 adrenergic receptor (beta 3 AR) were associated with differences of weight loss in obese patients submitted to a low calorie diet. DESIGN: Longitudinal, clinical intervention st udy of a 25% restriction in energy intake with respect to genotypes. S UBJECTS: 163 patients with a body mass index above 27. MEASUREMENTS: B ody weight and body mass index at baseline and after 2.5 months, genot ypes by polymerase chain reaction followed by enzymatic digestion. RES ULTS: For the UCP polymorphism, two alleles, 1 and 2 were identified w ith respective frequencies of 0.27 and 0.73. The allele 1 was associat ed with lower body weight loss after diet: 4,6, 5.7 and 7.1 kg for the 1-1, 1-2 and 2-2 genotypes respectively (P < 0.05). No difference in weight loss was found according to the beta 3 AR Trp64Arg mutation. CO NCLUSIONS: A genetic variant of the UCP gene is associated with a resi stance to low calorie diet. This result, together with previous data o n body weight gain, supports the hypothesis of a role of UCP and brown adipose tissue in the body weight regulation in humans. The importanc e of the Trp64Arg mutation of the beta 3 AR in the resistance to low c alorie diet is still to demonstrate.