Does Chronic Sweetener Intake Affect Learning?

Abstract

Artificial sweeteners are considered innocuous dietary complements used to replace sugarin a variety of commercial products. These additives are also used for the preventionor treatment of chronic illnesses such as diabetes and obesity, as well as forlosing weight. Among the most commonly used sweeteners we have sucralose, which recent studies have related to showing unwanted effects on metabolism.Due to the essential demand for glucose to supply the energetic requirements of the central nervous system (CNS), a decrease in its bioavailability disturbs signal conduction in the CNS and alters functions dependent on the specific area of the brain affected. This is particularly relevant for areas where neurogenesisoccurs, such as the olfactory bulb, striatum and hippocampus, which are related to cognitive processes involved in learning and memory formation.The objective of this study is to test spatial learning and memory through the Morris water mazein female BALB/c mice. Spatial learning in this task involves multiple cognitive components, such as problem solving, enhanced selective attention, formation of internal representations of the external world and storage and retrieval of relevant information. Based on principles for the use of animals in research and education, we used three groups of 8 week‐old mice: a control group (without supplementation), a sucrose group and a sucralose group (with sweetener supplemented in drinking water). The animals were supplemented for 5 weeks. After supplementation, mice were tested in a Morris water maze, where mice were trained on five consecutive days and on tested on day 6.Our results show significant differences in the amount of time taken to reach the platform, as well as time spent searching in the platform area and number of crossings over the platformarea, between the sucrose group and the sucralose and control groups, with mice from the sucrose group taking more time to reach the platform and spending lesstime in the platform area during training (p<0.001) compared to the control and sucralose groups; however, we did not find a statistical difference among groups on the final day. This situation is interesting, since there appear to be differences in the learning process during training, but those differences disappear by the end of the study period. Whether these differences are due to a modified animal behavior during training or to a compensatory mechanism that may balance an initially apparent learning deficiency requires further investigation related to the temporal course of supplementation and the molecular mechanisms involved. We are currently assessing molecular targets that may be relevant for these processes in our model.