Chronically exposure to stress promotes in individuals high intake of foods with high content of carbohydrates and fat and may develop obesity. Stress-induced sustained elevation of glucocorticoid serum levels may be due to impaired functioning of the hypothalamic glucocorticoid receptor GR, altering the hypothalamic-pituitary-adrenal axis regulation. As a result, chronically stressed individuals are unable to respond with higher cortisol levels when subjected to a new acute challenge. We hypothesized that obese patients that were exposed to chronic stress and classified as food-addicted will carry a risk polymorphism of NR3C1 gene (GR) and a blunted saliva cortisol concentration after taking a stress test. Our aim was the identification of a risk biomarker to develop food addiction and obesity by combined effects of genetic factors and chronic stress in patients attending Dietetics and Nutrition Clinic of Security Services for State Workers in Mexico City.
Two-generation Mexican patients (n=400) participated in a transversal study (approved by the Ethical committee of the National Institute of Psychiatry RFM), signing the informed agreement. Men and women between 18 and 49 years old had their body mass index (BMI) registered. Menopause, smoking and alcohol drinking were exclusion criteria. Participants answered Yales food addiction scale and a three-day food intake reminder. Before and after taking the Trier stress test, a sample of saliva was obtained and a previous sample of blood to evaluate cortisol levels and NR3C1 polymorphism presence.
Results showed higher prevalence of food addiction in obese patients (44%) than controls (31%); food-addiction was more prevalent in women (38%) than in men (25.5%); cortisol levels increased after stress test (170±71 vs. before=46±8 ng/mL) in patients with normal BMI but not in those with obesity (62±22 ng/mL vs. before=59±20 ng/mL); women with food-addiction had higher ratio of risk polymorphism AG-GG/AA of NC3C1 gene (0.56) than men or patients with no food addiction (0.34). Supported by CONACyT 233918 (FOSSIS)