A study published in the Journal of Food Science suggests that caffeine consumption may decrease the perceived intensity of sweet taste. Caffeine’s well-documented physiological effect on alertness originates from its actions as an antagonist of adenosine receptors in the brain. Findings demonstrating that adenosine receptors are expressed in sweet-sensitive taste cells of rodents suggest that caffeine consumed through foods has the potential to act on these receptors in taste, to decrease the perceived intensity of sweet stimuli. The researchers set out to find out if caffeinated coffee consumption can inhibit the perception of sweet taste in humans.
The researchers randomly assigned 107 panelists to two groups, sampling decaffeinated coffee supplemented with either 200 mg of caffeine (about the level found in a strong cup of coffee) or an equally bitter concentration of quinine. Participants subsequently performed sensory testing, with the session repeated in the alternative condition in a second session on a separate day.
The panelists rated both the sweetened coffee itself and subsequent sucrose solutions as less sweet in the caffeine condition, despite the treatment having no effect on bitter, sour, salty, or umami perception. In addition, panelists were also unable to discern whether they had consumed the caffeinated or noncaffeinated coffee, with ratings of alertness increased equally, but no significant improvement in reaction times, highlighting coffee’s powerful placebo effect.
The researchers concluded that, “This study demonstrates a real-world example of taste modulation from real food products, whereby caffeine from coffee consumption was able to suppress sweet taste in a long-lasting manner, consistent with rodent studies on active adenosine receptors in taste buds supporting sweet taste detection.”