Evaluation of the effects of high blood glucose and caffeine, individually and together, on cognition

• Grant number: 12/24758-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2013
• End date: December 31, 2013
• Field of knowledge: Humanities - Psychology - Physiological Psychology
• Principal Investigator: Sabine Pompéia
• Grantee: Laís Marquezim
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

This project aims to increase knowledge about the effects of caffeine and glucose, independently and in combination, on mood and cognitive performance (memory, attention) in healthy young males who consume caffeine. Given the widespread consumption of caffeine-containing products is important to understand in detail how it affects cognition and mood. To this end, it proposes a study in two steps: first glucose concentration profile for 90 min. after ingestion of a standardized meal with and without administration of a dose of caffeine, which is a double espresso (150 mg capsule). In theory, caffeine should increase blood glucose levels, but this has not been demonstrated for these doses, which neither what is its relationship with cortisol changes. The second step is to evaluate the effects of glucose on mood and cognitive effects of caffeine. A recent study showed that after food intake the caffeine plasma concentrations reach values close to the maximum only after about 120 minutes and remain elevated for more than 30 minutes. Thus will be evaluated the effects of caffeine on cognition and mood between 120 and 150 minutes after ingestion of caffeine in a situation of high blood glucose versus fasting. The experimental design is double-blind for caffeine intake, crossover, controlled with placebo and fasting, including 12 participants young healthy males who consume caffeine daily. These participants will be subjected to four treatments in random order: a) meal without caffeine b) meal with 150 mg of caffeine beyond the typical morning consumption of subjects c) fasting without caffeine d) fast with 150 mg of caffeine beyond the typical morning consumption of subjects. Will be measured capillary glucose, blood pressure, and heart rate every 20 minutes, and salivary cortisol, pupillary dynamics (measure of cognitive effort and effects of caffeine), and humor every 30 minutes. After 90 minutes of the treatment ingestion in feeding conditions, participants will consume more cereal bars. Thirty minutes later (time required for serum concentrations are reached near the peak of caffeine - step 2 of the study) will conduct a battery of cognitive tests and answer questionnaires assessing subjective feelings. Will be possible to determine how feeding affects the physiological effects of caffeine taken daily (step 1) and how glucose changes the mood and cognitive effects of caffeine and if is related to changes in cortisol. This project aims to complement data obtained in a study approved by UNIFESP CEP (Project No. 0050/11) which has funding from FAPESP (project No. 2011/01204-3) and will be conducted by an undergraduate student (Laís Marquezim) as completion of course work under the guidance of Sabine Pompéia of the UNIFESP Department of Psychobiology. (AU)