New research may help explain why a jelly donut goes so well with a strong cup of coffee. The study, conducted by researchers at Cornell University, shows that caffeine temporarily reduces tastebud sensations, making food and drink seem less sweet — and in turn, may actually make people crave more sweets.
“When you drink caffeinated coffee, it will change how you perceive taste — for however long that effect lasts. So if you eat food directly after drinking a caffeinated coffee or other caffeinated drinks, you will likely perceive food differently,” said senior author Robin Dando, assistant professor of food science.
Caffeine is a very strong antagonist of adenosine receptors, which tend to promote relaxation and sleepiness. So while suppressing these receptors makes people feel more energized, it appears to decrease their ability to taste sweetness.
The blind study investigated taste modulation in the real world. During the first experiment, one group sampled decaffeinated coffee with 200 milligrams of caffeine added in a laboratory setting, equal to a strong cup of coffee. The stimulant was added to make that group’s coffee consistent with real-life amounts of caffeine.
The second group drank just decaffeinated coffee. Both groups had sugar added. Participants who drank the brew with caffeine rated it as tasting less sweet.
In the second half of the study, the researchers discovered that there may be a mild placebo effect in the act of drinking coffee. After drinking their coffee, the participants were asked to report their level of alertness and estimate the amount of caffeine in their coffee.
Notably, the volunteers reported the same increase in alertness after drinking either the caffeinated or decaffeinated samples, and were unable to predict whether they had consumed the decaffeinated or the caffeinated version.
“We think there might be a placebo or a conditioning effect to the simple action of drinking coffee,” said Dando. “Think Pavlov’s dog. The act of drinking coffee — with the aroma and taste — is usually followed by alertness. So the panelists felt alert even if the caffeine was not there,” said Dando.
“What seems to be important is the action of drinking that coffee,” Dando said. “Just the action of thinking that you’ve done the things that make you feel more awake, makes you feel more awake.”
Dando, along with lead authors Ezen Choo and Benjamin Picket published their findings in an article titled, “Caffeine May Reduce Perceived Sweet Taste in Humans, Supporting Evidence That Adenosine Receptors Modulate Taste,” in the Journal of Food Science.
Source: Cornell University