Cannabinoid Type 1 Receptor Gene Polymorphism And Macronutrient Intake

in vivo · May 9, 2014

The endocannabinoid system controls food intake, energy balance, and lipid and glucose metabolism [1]. It has both central and peripheral effects and stimulates lipogenesis and fat accumulation [1]. Moreover, there is evidence suggesting that cannabinoid type 1 receptor (CB1-R) and endocannabinoids are involved in regulating the energy balance, influencing eating behavior and body weight [2]. The endocannabinoid system is overactivated in genetic animal models of obesity and in response to exogenous stimuli such as excessive food intake [3,4].

A greater insight into the endocannabinoid system has been gained from studies in animals with a genetic deletion of CB1-R, which have a lean phenotype and are resistant to diet-induced obesity and the associated insulin resistance produced by a highly palatable high-fat diet [6].

Several studies have shown an association between CB1-R gene polymorphisms and obesity in humans [12,13,14,15,16]. Previously, we evaluated, at the population level, the frequency of a genetic polymorphism of the CB1-R gene (1359 G/A) and its correlation with body mass index (BMI), showing that the presence of the CB1 polymorphic A allele was significantly associated with a lower BMI [17].

Background: Cannabinoid type 1 receptor (CB1-R) is a key mediator in the control of food intake and is linked to obesity.

Aim: To evaluate the relationship between CB1-R gene polymorphism and dietary macronutrient intake in elderly subjects.

Methods: This study included 118 subjects (60 males, 58 females) from a population survey carried out in southern Italy in 1992–1993 who were older than 65 years and previously characterized for CB1-R polymorphism (75 with GG wild-type genotype, 41 with heterozygous polymorphic allele AG, and 2 with genotype AA). All subjects completed a validated semi-quantitative food frequency questionnaire. Statistical methods included multiple logistic regression to model macronutrient intake to genotype, controlling for potential confounders.

Results: When controlled for age, gender, and body mass index, the intake of dietary cholesterol and saturated fats corrected for calories was inversely associated with the CB1-R 1359 G/A polymorphism, while the intake of starchy carbohydrates was directly associated with this polymorphism.

Conclusion: In our unselected elderly population, the 1359 G/A polymorphism is linked with a specific macronutrient intake. This could be explained by the role of the cannabinoid system as a determinant of food intake and eating behavior.