Dietary-fat effect of the rs10830963 polymorphism in MTNR1B on insulin resistance in response to 3 months weight-loss diets

Abstract

Background and aimsThe risk allele (G) of rs10830963 in the melatonin receptor 1B (MTNR1B) gene presents an association with obesity. We study the effect of this SNP on cardiovascular risk factors and weight loss secondary to 2 hypocaloric diets. Methods361 obese subjects were randomly allocated during 3 months (diet M – high monounsaturated fat hypocaloric diet vs. diet P – high polyunsaturated fat hypocaloric diet). Anthropometric parameters, fasting blood glucose, C-reactive protein (CRP), insulin concentration, insulin resistance (HOMA-IR), lipid profile and adipocytokines levels were measured. Genotype of MTNR1B gene polymorphism (rs10830963) was evaluated. ResultsAll anthropometric parameters, systolic blood pressure and leptin levels decreased in all subjects after both diets. This improvement of anthropometric parameters was higher in non G allele carriers than G allele carriers. After dietary intervention with diet M (CC vs. CG+GG); total cholesterol (delta: −10.4±2.1mg/dl vs. −6.4±1.2mg/dl: p<0.05), LDL-cholesterol (delta: −7.1±0.9mg/dl vs. −2.8±0.8mg/dl: p<0.05), insulin (delta: −3.0±0.8UI/l vs. −2.0±1.0UI/l: p<0.05) and HOMA-IR (delta: −3.4±1.0units vs. −2.9±0.9units: p<0.05) improved in no G allele carriers. After diet P, in the group of subjects without G allele CC, insulin levels (delta: −2.9±1.0UI/l vs. −0.6±0.2UI/l: p<0.05) and HOMA-IR (delta (CC vs. CG+GG): −0.8±0.2units vs. −0.4±0.3units: p<0.05) decreased, too. ConclusionsOur study detected a relationship of rs10830963 MTNR1B SNP with body weight loss and insulin resistance modification induced by 2 different hypocaloric. Only monounsaturated enriched hypocaloric diet and in no-G allele carriers showed a significant effect on lipoproteins.