Coffee is the choice elixir of night owls, professionals, new moms and the sleep deprived alike. For some, it’s the sound of the bubbling water, for others it’s the aromatic, earthy smell that creeps through their morning-lit kitchens. Many will agree, though, that the appeal is the jolt of energy that quickly follows their morning cup of joe—thank you, caffeine.
Caffeine, found in coffee, energy drinks, soda and even chocolate, stimulates neurotransmission in the central nervous system (the noggin) to prevent the onset of drowsiness. This increase in communication between areas in the brain results in the caffeine “buzz” associated with coffee. However, an additional effect of caffeine is a narrowing of the blood vessels in the brain, causing a reduction in blood flow. This decrease in blood flow is an undesirable effect because adequate blood flow is associated with better brain function. Researchers hypothesize that coupling the stimulatory effects of caffeine with a strategy to increase blood flow will result in greater cognitive function. Dr. O’Connor at the University of Georgia aimed to test the effects of the brain stimulatory effect of caffeine coupled with the vessel dilating effects of polyphenols in apple juice1.
The experiment included placebo drinks, a caffeine control and apple juice “caffeine cocktails” with varying levels of caffeine. Researchers investigated their effects on motivation, sustained attention and reaction time. In the lab, participant’s tasks were quite tedious number identification exercises, but in a real life scenario, these measurements can translate to:
- Desire/motivation to buckle down and get to work
- How long focus can be maintained and accuracy of the work completed
- How quickly work is performed
His experiments revealed that apple juice with about 40 mg of caffeine (the amount in about ½ cup of green tea2) yielded comparable or better results than the apple juice with 75 mg caffeine (the amount in about ½ cup of coffee). The apple juice with ~40 mg caffeine increased motivation, sustained attention and resulted in a faster reaction time compared to the other beverages and the placebo.
Should you guzzle the coffee for the caffeine, or “spiked” apple juice for the additional polyphenolic effects? More research is needed to say with certainty but this new evidence is quite exciting. Practitioners can add this “cognitive” piece of the caffeine puzzle to the extensive research on coffee and caffeinated beverages. Most importantly, and not covered in Dr. O’Connor’s talk, is the safety of caffeine. According to the Dietary Guidelines for Americans, up to 400 mg of caffeine can be incorporated into healthy eating patterns(3) This may be the sweet spot for those desiring the cognitive benefits of coffee while still balancing a healthy lifestyle. Dr. O’Connor made one point clear, that “caffeine effects how you feel as much as it affects how you perform”. Coffee drinkers, unite, and celebrate over your favorite (cold) brew.
- O’Connor P. Effects of Low Doses of Caffeine Added to Apple Juice and Cocoa on Mental Energy. Department of Foods and Nutrition Seminar. Athens, GA. August 31, 2016.
- Cabrera C, Reyes A, and Giménez R. Beneficial effects of green tea—a review. Journal of the American College of Nutrition. 2006;25:2:79-99.
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.
I found this very interesting to me. I am an avid coffee drinker & as a child I was constantly drinking apple juice. I throughly enjoy the taste of coffee whether I am drinking it black, or with a very small amount of cream. I also enjoy coffee for the caffeine aspect of it to wake up in the morning and if I don’t drink it in the morning, then come a few hours later I have an awful headache. But then I can also drink a cup of coffee at night and have no problem falling asleep. I’m not sure if my brain is really just tricking my body or if I have come immune to the effects of caffeine because of how much I consume. I found it very interesting in this article that the results showed His experiments revealed that apple juice with about 40 mg of caffeine (the amount in about ½ cup of green tea2) yielded comparable or better results than the apple juice with 75 mg caffeine. I would like to know the reasoning and research in a more detailed conclusion as to why the apple juice with the smaller amount of caffeine yielded better results in attention span & increased motivation.
I thought this post/article was extremely interesting. My father has worked for Starbucks Coffee Company since I was 12 or 13 years old, so naturally, whether good or bad I grew up on their product. I am without a doubt a coffee, but, even more so, a caffeine addict. As you state in your post, I definitely agree that a major appeal for me “is the jolt of energy that quickly follows”, especially as I become a young professional and try to keep up with a busy schedule. I thought it was especially interesting to see that the 40mg caffeine trial combined with the polyphenols in apple juice provided better results such as “increased motivation, sustained attention and resulted in a faster reaction time” compared to the 75mg caffeine and polyphenol trial. I think it would be beneficial to do more research on this because the general population will reach for a “venti” at Starbucks in hopes of getting a greater “energy boost” when maybe they should be grabbing a tall? I also am curious to see more research as to weather the source of polyphenols have anything to do with the effects. For example, I’d be interested to see if caffeine combined with cocoa powder/ dark chocolate or even red wine (foods rich in Polyphenols) would have the same effects.
This article is fascinating to me as it brings focus on the cognitive effects of caffeine in addition to the physical energy level effects. Most individuals, as you state in your article, would agree that they drink coffee for the jolt of energy. I however usually find that drinking coffee or caffeine is more of a psychological thing for me. I don’t necessarily need to have a very large cup of coffee, but just a small amount at the beginning and middle of my days makes me feel more energized, whether physiologically that is actually the case is another story. I think this makes more sense to me now knowing that I could potentially actually be benefitting my cognitive functioning by having a smaller amount of caffeine at once. I suspect this may be a rather new finding as I have never heard it mentioned before, but I definitely think it deserves more attention and research to determine its benefits!