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Coffee boosts mental alertness, and it’s not just the caffeine

I don’t think it’s surprising that we know that coffee is brain-boosting by making you more alert — what is surprising is that it may not be caffeine that causes this, but it could be other biochemicals that are linked to this. A new paper describes what components of coffee, other than caffeine, may be linked to boosting brain alertness.

I have written about how coffee may have some important effects on humans, both positive and negative, but I’ve never read any research about the most obvious effects of coffee, that is, boosts to alertness. So this new research was particularly interesting to me.

As I usually do, let’s take a look at this new article along with my critique of it.

black espresso maker with cup
Photo by Viktoria Alipatova on

Coffee and caffeine paper

In a paper published on 28 June 2023 in Frontiers in Behavioral Neuroscience, Nuno Sousa, MD, Ph.D., with the University of Minho, Braga, Portugal, and colleagues examined how coffee boosts alertness and psychomotor performance and what compounds in coffee, other than caffeine, that may contribute to these effects.

To examine these brain-boosting effects, the researchers investigated the neurobiological impact of coffee drinking on brain connectivity using resting-state functional magnetic resonance imaging (fMRI), which detects blood flow to various parts of the brain. Usually, if a part of the brain is in use, blood flow increases..

The researchers 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 the 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 (in effect, a placebo), 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. This should show the effect of caffeine alone versus coffee.

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 observation may show that consuming either coffee or caffeine heightened individuals’ readiness to transition from a state of rest to engaging in task-related activities.

But there’s more. Drinking a cup of coffee also boosted connectivity in the higher visual network of the brain and the right executive control network. These two networks are linked to working memory, cognitive control, and goal-directed behavior, which were not observed in individuals who drank plain caffeinated water.

So, the boosting of the brain’s activities was something more than just the caffeine in the coffee. Other compounds in coffee, such as Certain compounds in coffee, such as chlorogenic acids, have well-documented psychoactive effects, but the researchers did not test that directly.


This research is rather cutting-edge, so we are a long way from declaring that coffee makes you smarter or better in any meaningful manner. I think the next study would be some sort of double-blind clinical trial that includes a placebo (caffeinated water), decaf coffee, and regular coffee.

If there are other compounds at work in boosting brain function, the decaf coffee might have them, unless, of course, those compounds are also removed when the coffee undergoes the decaffeination process.

I think most of us know that coffee gives us a “kick” to the brain, but we probably always thought that it was the caffeine that did it. But this preliminary research seems to indicate it’s more than just caffeine — coffee has some other compounds that boost executive function and other brain functions.

Because this study is so small and preliminary, I can only give it two out of five stars. I’m intrigued by the value of coffee in boosting mental alertness, beyond just caffeine, but I need to see more and larger studies before shouting from the rooftops that coffee is the miracle drink.


Michael Simpson

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