After an over indulgent snack we’ve all felt the sugar coma ensue. How much of this is mental versus physiological? In recent years there has been increasing interest in studying cognitive eﬀects associated with sugar consumption. In a newly published study, Rachel Ginieis aims to test the eﬀects of different sugars on selected cognitive tasks, using a double-blind, cross-over experimental design. Rather than focusing exclusively on a particular cognitive domain, the study is designed to include a variety of tasks that implicate prefrontal lobe functioning, which include information processing, executive functioning and attention.
To test these effects the research team set up four experimental sessions, in which each participant consumed sweetened drinks: glucose, sucrose, fructose and a placebo sucralose. As the authors state, “overall, the ﬁndings showed that glucose and sucrose had relatively negative eﬀects on the assessed cognitive tasks. In contrast, no apparent eﬀect on task performances was found with fructose ingestion compared to the placebo.” In other words the ingestion of glucose was correlated with lower cognitive ability on a number of cognitive tasks.
By testing a number of sugars, the authors are able to conclude that the “cognitive eﬀects of sugar are unlikely moderated by the perception of sweetness. Rather, the eﬀects are mediated by glucose.” So, you may want to consider holding off on that craving until after any exams or other cognitive tasks are complete.
The paper, The “sweet” effect: Comparative assessments of dietary sugars on cognitive performance, was co-authored by Elizabeth A. Franz, Indrawati Oey, Mei Peng.