Genetic variation in the endocannabinoid degrading enzyme fatty acid amide hydrolase (FAAH) and their influence on weight loss and insulin resistance under a high monounsaturated fat hypocaloric diet

Background and Aims: The C385A polymorphism of FAAH gene (rs324420C>A) has been associated with obesity. We investigate the role of this polymorphism on anthropometric and metabolic responses after an enriched monounsaturated fat hypocaloric diet. Methods: A sample of 95 obese individuals was analyzed at baseline and after 3 months of an enriched monounsaturated fat hypocaloric diet. Results: Sixty two patients (653%) had the genotype C385C and 33 (34.7%) patients had C385A genotype (30 patients, 31.6%) or A358A (3 patients, 3.2%) (A carriers group). In subjects with C385C genotype, insulin (-1.9 +/- 5.3 mUl/l) and HOMA-R (-0.48 +/- 0.75 U) decreased. In A carriers subjects, the decreases in weight were 3.7 +/- 3.4 kg (decrease in C385C genotype group 4.4 +/- 3.6 kg), fat mass 2.7 +/- 3.2 kg (decrease in C385C genotype group 3.4 +/- 3.2 kg) and waist circumference 3.1 +/- 3.4 cm (decrease in C385 genotype group 4.4 +/- 4.6 cm). These changes were significantly higher in the C385C genotype group than the A carriers subjects. Conclusion: After weight loss, noncarriers of the allele A385 of FAAH had an improvement on insulin and HOMA-R levels with an enriched monounsaturated fat hypocaloric diet. A better response of weight, fat mass and waist circumference was observed in C385 genotype subjects than A carriers participants. (C) 2013 Elsevier Inc. All rights reserved.