Coffee’s ability to boost alertness is commonly attributed to caffeine, but new research suggests there may be other underlying mechanisms that explain this effect.
“There is a widespread anticipation that coffee boosts alertness and psychomotor performance. By gaining a deeper understanding of the mechanisms underlying this biological phenomenon, we pave the way for investigating the factors that can influence it and even exploring the potential advantages of those mechanisms,” study investigator Nuno Sousa, MD, PhD, with the University of Minho, Braga, Portugal, said in a statement.
The study was published online June 28 in Frontiers in Behavioral Neuroscience.
Caffeine Can’t Take All the Credit
Certain compounds in coffee, including caffeine and chlorogenic acids, have well-documented psychoactive effects, but the psychological impact of coffee/caffeine consumption as a whole remains a matter of debate.
The researchers investigated the neurobiological impact of coffee drinking on brain connectivity using resting-state functional magnetic resonance imaging (fMRI).
They recruited 47 generally healthy adults (mean age, 30; 31 women) who regularly drank a minimum of one cup of coffee per day. Participants refrained from eating or drinking caffeinated beverages for at least 3 hours prior to undergoing fMRI.
To tease out the specific impact of caffeinated coffee intake, 30 habitual coffee drinkers (mean age, 32; 27 women) were given hot water containing the same amount of caffeine, but they were not given coffee.
The investigators conducted two fMRI scans ― one before, and one 30 minutes after drinking coffee or caffeine-infused water.
Both drinking coffee and drinking plain caffeine in water led to a decrease in functional connectivity of the brain’s default mode network, which is typically active during self-reflection in resting states.
This finding suggests that consuming either coffee or caffeine heightened individuals’ readiness to transition from a state of rest to engaging in task-related activities, the researchers note.
However, drinking a cup of coffee also boosted connectivity in the higher visual network and the right executive control network, which are linked to working memory, cognitive control, and goal-directed behavior ― something that did not occur from drinking caffeinated water.
“Put simply, individuals exhibited a heightened state of preparedness, being more responsive and attentive to external stimuli after drinking coffee,” said first author Maria Picó-Pérez, PhD, with the University of Minho.
Given that some of the effects of coffee also occurred with caffeine alone, it’s “plausible to assume that other caffeinated beverages may share similar effects,” she added.
Still, certain effects were specific to coffee drinking, “likely influenced by factors such as the distinct aroma and taste of coffee or the psychological expectations associated with consuming this particular beverage,” the researcher write.
The investigators report that the observations could provide a scientific foundation for the common belief that coffee increases alertness and cognitive functioning. Further research is needed to differentiate the effects of caffeine from the overall experience of drinking coffee.
A limitation of the study is the absence of a nondrinker control sample (to rule out the withdrawal effect) or an alternative group that consumed decaffeinated coffee (to rule out the placebo effect of coffee intake) ― something that should be considered in future studies, the researchers note.
The study was funded by the Institute for the Scientific Information on Coffee. The authors declare no relevant conflicts of interest.
Front Behav Neurosci. Published online June 28, 2023. Full text
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