Food & Function PAPER Cite this: Food Funct., 2017, 8, 2592 Received 15th March 2017, Accepted 30th June 2017 DOI: 10.1039/c7fo00408g rsc.li/food-function Early maternal separation induces preference for sucrose and aspartame associated with increased blood glucose and hyperactivity L. Aya-Ramos, a C. Contreras-Vargas, a J. L. Rico b and Z. Dueñas * a Early life stress and exposure to sweeteners lead to physiological and behavioral alterations in adulthood. Nevertheless, many genetic and environmental factors as well as the neurobiological mechanisms that contribute to the development of these disorders are not fully understood. Similarly, evidence about the long-term metabolic effects of exposure to sweeteners in early life is limited and inconsistent. This study used an animal model of maternal separation during breastfeeding (MS) to analyze the effects of early life stress on consumption of sweeteners, weight gain, blood glucose and locomotion. Rats were housed under a reversed light/dark cycle (lights off at 7:00 h) with ad libitum access to water and food. In the MS protocol, MS pups were separated from the dam for 6 h per day in two periods of 180 minutes (7:00–10:00 and 13:00–16:00 h) during the dark phase of postnatal day (PND) 1 to PND 21. Non-separated (NS) pups served as controls. On PND 22 rats were grouped by sex and treatment. From PND 26 to PND 50 sucrose and aspartame were provided to rats, and sweetener intake, body weight and blood glucose-related measures were scored. On PND 50, both male and female rats were exposed to the open field test to obtain locomotion and anxiety-related measures. Results showed that both early maternal separation and sweetener intake during adoles- cence resulted in increased blood glucose and hyperactivity in male rats but not in female rats. Data suggest that the combination of early stress and exposure to sucrose and aspartame could be a risk factor for the development of chronic diseases such as diabetes, as well as for behavioral alterations. Introduction Neonatal maternal separation of laboratory animals is an animal model of stressful experiences such as maternal neglect or abuse in early life. 1,2 Patients who have eating dis- orders and dysfunctional hypothalamic–pituitary–adrenal axes (HPA) are commonly found to have been abused during child- hood. 3,4 It has also been shown that an adverse environment in early life is linked to greater susceptibility to development of various adult diseases including mental disorders, diabetes and obesity. 5 In fact, experimental studies in rodents have shown that the presence of the dam during lactation is crucial for avoiding negative effects on neurological development of pups. 6 On the other hand, being overweight or obese has also been linked to psychiatric disorders such as depression and anxiety, 9 and the prevalence of these conditions has been increasing worldwide. 7 Obesity has been strongly linked to the development of metabolic syndrome which is defined as a set of risk factors for cardiovascular disease and type 2 diabetes mellitus that includes hypertension, dyslipidemia, increased fasting glucose and central obesity. 8 Although there is no single factor responsible for the significant increases in over- weight and obesity that have emerged over the last decades, current evidence suggests that the consumption of sucrose and aspartame is part of this problem. 10 It is also known that availability and use of caloric sugar substitutes has increased and that consumers have been led to believe that these pro- ducts are healthier. 11 However, epidemiological data from various cohorts show that the use of caloric sweeteners con- tributes to development of type 2 diabetes mellitus, coronary heart disease and strokes. 12 Many studies have indicated a strong correlation between maternal separation and other traumatic events during early life on the development of behavioral and neuroendocrine a Universidad Nacional de Colombia, Bogotá, Facultad de Medicina, Departamento de Ciencias fisiológicas, Grupo neurobiología y comportamiento, Bogotá, D.C. 11001, Colombia. E-mail: zjduenasg@unal.edu.co b Fundación Universitaria Konrad Lorenz, Facultad de Psicología, Bogotá, D.C., Colombia 2592 | Food Funct. , 2017, 8, 2592–2600 This journal is © The Royal Society of Chemistry 2017 Published on 03 July 2017. Downloaded by Universidade Federal do Rio Grande do Sul on 1/30/2019 3:27:46 PM. View Article Online View Journal | View Issue