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 AimsThe 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.MethodsA sample of 95 obese individuals was analyzed at baseline and after 3 months of an enriched monounsaturated fat hypocaloric diet.ResultsSixty two patients (65.3%) 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 mUI/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.ConclusionAfter 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.