European researchers have found that the boost people get from a morning coffee cannot be replicated with plain caffeine.
The Iberian team found that plain caffeine only partially reproduced the effects of drinking a cup of coffee, activating the sensation of alertness but not the areas of the brain that impact working memory and goal-directed behaviour.
Field Chief Editor of the journal Frontiers in Behavioural Neuroscience, Professor Nuno Sousa of the University of Minho, pointed out that there is a common expectation that coffee increases alertness and psychomotor functioning.
“Habitual coffee consumers justify their life choices by arguing that they become more alert and increase motor and cognitive performance and efficiency, however, these subjective impressions still do not have a neurobiological correlation,” he said.
The team recruited people who drank a minimum of one cup of coffee a day and asked them to refrain from eating or drinking caffeinated beverages for at least three hours before the study.
They interviewed the participants to collect sociodemographic data, and then did two brief functional MRI scans: one before and one 30 minutes after either taking caffeine or drinking a standardised cup of coffee, and during the scans, the participants were asked to relax and let their minds wander.
Because of the known neurochemical effects of drinking coffee, the scientists expected that the functional MRI scans would show that the people who drank coffee had higher integration of networks linked to the prefrontal cortex and the default mode network (DMN).
However, they found that the connectivity of the DMN – involved in introspection and self-reflection processes – was decreased both after drinking coffee and after taking caffeine, indicating that consuming either caffeine or coffee made people more prepared to move from resting to working on tasks.
“Drinking coffee also increased the connectivity in the higher visual network and the right executive control network – parts of the brain which are involved in working memory, cognitive control, and goal-directed behaviour,” Professor Sousa said.
“This didn’t happen when participants only took caffeine, or in other words, if you want to feel not just alert but ready to go, caffeine alone won’t do – you need to experience that cup of coffee.”
Lead author Dr Maria Picó-Pérez of Portugal’s Jaume I University said that explained that subjects were more ready for action and alert to external stimuli after having coffee.
“Taking into account that some of the effects that we found were reproduced by caffeine, we could expect other caffeinated drinks to share some of the effects; yet others were specific to drinking coffee, driven by factors such as the particular smell and taste of the drink, or the psychological expectation associated with consuming that drink,” she said.
The authors pointed out that the experience of drinking coffee without caffeine could cause these benefits, as the study could not differentiate the effects of the experience alone from the experience combined with the caffeine.
There was also a hypothesis that the benefits coffee-drinkers claim could be due to the relief of withdrawal symptoms, which the study did not test.