Genetic Evidence of Endocannabinoid System on Perceived Stress and Restricted Food Intake: The Role of Variants rs324420 in FAAH Gene and rs1049353 in CNR1 Gene.

Background: The endocannabinoid system (ECS) is active in brain regions involved in stress, food intake, and emotional regulation. The CB1 receptor and the fatty acid amide hydrolase (FAAH) enzyme regulate the ECS. Genetic variants in the FAAH gene (rs324420) and in the CNR1 gene (rs1049353) have been involved in both chronic stress and obesity. As a maladaptive strategy to evade the stress, three dysfunctional eating patterns may appear: cognitive restriction, disinhibition, and emotional eating. Aim: To evaluate the association of variants rs324420 in the FAAH gene and rs1049353 in the CNR1 gene with perceived stress, dysfunctional eating patterns, and anthropometric and body composition variables. Methods: This cross-sectional study included 189 participants from western Mexico. The Spanish version of the Three-Factor Eating Questionnaire and the Perceived Stress Scale were applied. Genotyping was performed with TaqMan^® probes. Results: It was found that subjects with CA/AA genotypes in FAAH had a higher risk of presenting high scores in stress perception than CC genotype carriers (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.007-3.339; p = 0.048); in addition, the CC genotype of this genetic variant was related to higher body weight and body fat, but no association was found with dysfunctional eating patterns. As for the CNR1 single-nucleotide polymorphism, this variant showed no significant association with stress perception scores, but subjects with GA/AA genotypes in CNR1 had a lower risk of presenting high scores of restriction in food intake compared with GG genotype carriers (OR 0.11, 95% CI 0.046-0.322; p < 0.001). Therefore, this study suggests a differential role of the ECS genes FAAH and CNR1 in perceived stress and dysfunctional eating patterns, respectively. Further studies in other populations are required.