Cognitive and physiological effects of an “energy drink”: an evaluation of the whole drink and of glucose, caffeine and herbal flavouring fractions
- 5.8k Downloads
Both glucose and caffeine can improve aspects of cognitive performance and, in the case of caffeine, mood. There are few studies investigating the effects of the two substances in combination.
We assessed the mood, cognitive and physiological effects of a soft drink containing caffeine and glucose as well as flavouring levels of herbal extracts. The effects of different drink fractions were also evaluated.
Using a randomised, double-blind, balanced, five-way crossover design, 20 participants who were overnight fasted and caffeine-deprived received 250 ml drinks containing 37.5 g glucose; 75 mg caffeine; ginseng and ginkgo biloba at flavouring levels; a whole drink (containing all these substances) or a placebo (vehicle). Participants were assessed in each drink condition, separated by a 7-day wash-out period. Cognitive, psychomotor and mood assessment took place immediately prior to the drink then 30 min thereafter. The primary outcome measures included five aspects of cognitive performance from the Cognitive Drug Research assessment battery. Mood, heart rate and blood glucose levels were also monitored.
Compared with placebo, the whole drink resulted in significantly improved performance on “secondary memory” and “speed of attention” factors. There were no other cognitive or mood effects.
This pattern of results would not be predicted from the effects of glucose and caffeine in isolation, either as seen here or from the literature addressing the effects of the substances in isolation. These data suggest that there is some degree of synergy between the cognition-modulating effects of glucose and caffeine which merits further investigation.
KeywordsGlucose Caffeine Ginseng Ginkgo biloba Cognition Mood Heart rate Blood glucose
This work was funded by GlaxoSmithKline Consumer Healthcare R&D, Slough, UK. The authors are grateful to the anonymous reviewers for their positive and helpful comments.
- Bond A, Lader M (1974) The use of analogue scales in rating subjective feelings. Br J Psychol 47:211–218Google Scholar
- Gold PE (1995) Role of glucose in regulating the brain and cognition. Int J Clin Nutr 61:987–995Google Scholar
- Green PJ, Kirby R, Suls J (1996) The effects of caffeine on blood pressure and heart rate: a review. Ann Behav Med 18:201–216Google Scholar
- Hayman M (1942) Two minute clinical test for measurement of intellectual impairment in psychiatric disorders. Arch Neurol Psychiatry 47:454–464Google Scholar
- Kennedy DO, Wake G, Savealev S, Tildesley NTJ, Perry EK, Wake G, Wesnes KA, Scholey AB (2003) Modulation of mood and cognitive performance following administration of single doses of Melissa officinalis (lemon balm) with human CNS nicotinic and muscarinic receptor binding properties. Neuropsychopharmacology 28:1871–1881CrossRefPubMedGoogle Scholar
- Keppel G (1991) Design and analysis. Prentice Hall, New JerseyGoogle Scholar
- Keul J, Huber G, Lehman M, Berg A, Jakob EF (1982) Einfluss von Dex-trose auf Fahrleistung, Konzentrationsfaehigkeit, Kreislauf und Stoff-wechsel in Kraftfahrzeug-simulator (Doppelblind-studie im Cross-over Design). Akt Ernahr Mad 7:7–14Google Scholar
- Koelega HS (1998) Effects of caffeine, nicotine and alcohol on vigilance performance. In: Snel J, Lorist M (eds) Nicotine, caffeine and social drinking. OPA, Amsterdam, pp 363–373Google Scholar
- Korol DL, Gold PE (1998) Glucose, memory, and aging. Am J Clin Nutr 67(Suppl):764–771Google Scholar
- Loor M, McNair D (1980) Profile of mood states. Educational and Industrial Testing Service, San DiegoGoogle Scholar
- Rusted JM, Warburton DM (1991) Molecules for modelling cognitive impairment. In: Hindmarch I, Hippius H, Wilcox G (eds) Dementia, molecules, methods and measurement. Academic, LondonGoogle Scholar
- Scholey AB (2001) Fuel for thought. Psychologist 14:196–201Google Scholar
- Smith AP (2000) Behavioral effects of caffeine. In: Parliament TH, Ho C-T, Schieberle P (eds) Caffeinated beverages: health benefits, physiological effects, and chemistry. Oxford University, New York, pp 30–45Google Scholar
- Taylor LA, Rachman SJ (1987) The effects of blood sugar levels changes on cognitive function, affective state and somatic symptoms. J Behav Med 20:544–549Google Scholar
- Weschler D (1958) The measurement and appraisal of human intelligence, 4th edn. Williams & Wilkins, BaltimoreGoogle Scholar