Fuels for memory: the role of oxygen and glucose in memory enhancement

Abstract

Recent studies indicate that some aspects of memory can be enhanced by the administration of oxygen or glucose. Considering the dependency of glucose metabolism upon oxygen supply, the present study predicted that administering a combination of 100% oxygen with glucose would have greater memory-enhancing effects than when either substance was administered alone. In a placebo-controlled study, 104 healthy adults were given a glucose or placebo drink, and inhaled 100% oxygen or air for 1 min, before carrying out a number of everyday memory tasks designed to measure short-term and long-term memory. Results showed support for the enhancing effects of oxygen (but not for glucose) on delayed recall. These findings are discussed in relation to the possible cholinergic properties of oxygen and glucose and the implications for their clinical use.

Oxygen saturation and cognitive performance

“…Enhanced blood oxygen saturation levels do not seem (in our laboratory) to be important on their own, but could in combination with an increase of glucose level reveal effects beyond the effect obtained by manipulating only one of the two variables responsible for energy utilization for the brain. This hypothesis was supported by the results published by Winder and Borrill (1998). Their data revealed that the combination of breathing oxygen and glucose administration enhanced performance.…”

The effect of glucose dose and fasting interval on cognitive function: a double-blind, placebo-controlled, six-way crossover study

“…An effect of word recognition speed was observed in which 60 g glucose resulted in faster reaction times compared to placebo following an overnight fast suggesting that for recognition speed, under conditions of greater depletion of glucose resources participants might benefit from a higher glucose load. While effects of glucose on word recall are generally regarded as 'robust', a number of studies have failed to observe effects of glucose (25-50 g) on immediate word recall (Craft et al 1994;Ford et al 2002;Foster et al 1998;Green et al 2007;Scholey et al 2001;Scholey and Kennedy 2004;Winder and Borrill 1998) and delayed word recall (Craft et al 1994;Messier et al 1999;Scholey and Kennedy 2004;Winder and Borrill 1998;Scholey et al 2009a). Messier et al (1999) reported that the effects of 50 g glucose on free word recall was dependent on glucoregulatory processes, where glucose ingestion reversed the performance decrement associated with poor glucoregulation but did not impact on participants with better glucoregulation.…”

Cognitive Enhancement: Methods, Ethics, Regulatory Challenges

“…Since then several families of memory enhancing drugs affecting different aspects of long-term memory have been discovered. They include stimulants (Lee and Ma 1995;Soetens et al 1993;Soetens et al 1995), nutrients (Korol and Gold 1998;Foster et al 1998;Meikle et al 2005;Winder and Borrill 1998) and hormones (Gulpinar and Yegen 2004), cholinergic agonists (Iversen 1998;Power et al 2003;Freo et al 2005), the piracetam family (Mondadori 1996), ampakines (Lynch 1998;Ingvar et al 1997), and consolidation enhancers (Lynch 2002).…”