Updated: Mar 21
We love our morning cup of caffeine but does a daily jolt do a body good? We're spilling the tea, pro and con, about this popular stimulant.
Sure, caffeine, a central nervous stimulant, gives us a boost of energy. It can help make us more vigilant while navigating long car drives or feel mentally prepared to take on morning meetings. But that's not all.
A number of studies have found that caffeine may help improve overall task performance. In a 2018 study published in the journal Frontiers in Human Neuroscience, 20 participants took multiple tests before and after drinking caffeine and a placebo. Under the influence of caffeine, the task accuracy and response time of test-takers significantly improved.
And in a 2016 University of Arizona study, college students who drank a caffeinated beverage showed a 30 percent increase in recall compared to students who sipped a decaffeinated drink.
Not All Caffeine Buzzes are Alike
The source of your caffeine can make a difference in how it makes you feel. "Caffeine from tea, like green tea or matcha, might give you a calmer buzz than the perk you'll get from coffee," says Keri Gans, RDN. That's because green tea contains the amino acid L-theanine, which helps you absorb caffeine more slowly. Tea lovers, fear not - you still get the improved performance of caffeine, but often without the jitters.
How Much Caffeine Is in Common Foods & Beverages?
16 oz. energy drink 80 to 500 mg.
2 oz. espresso 126 mg.
1 cup brewed coffee 96 mg.
1 cup black tea 47 mg.
12 oz. soft drink 30-40 mg.
1 cup green tea 29 mg.
1 oz. dark chocolate 24 mg.
Source: U.S. Dept. of Agriculture
The Dehydrating Myth
Because caffeine is a mild diuretic, there is a long-standing myth that it's dehydrating. That myth has been busted: "The impact of the diuretic effect is less than the amount of liquid you're consuming in a cup of caffeinated beverage," says Keri Gans, RDN.
If a beverage is labeled "decaffeinated," it doesn't mean it has zero milligrams of caffeine. Typically, a cup of decaf coffee contains 2 to 15 milligrams of caffeine, according to the Food and Drug Administration. [Decaffeinated black tea contains about 2 grams of caffeine.]
Source: Written by Marge Perry, Excerpts from Keen on Caffeine, AllRecipes, February/March 2023.