A cause for social interaction, a curer of hangovers and a saviour from exhaustion, coffee is by far one of our most valuable products in the modern world. 125 million people worldwide depend on coffee for their livelihoods and that comes as no surprise as there are 55 million cups being drunk in a single day across the planet.
Coffee was discovered in the 9th century by an Ethiopian goat herder who saw how excited Arabica beans made his goats- I can only imagine his confusion until he realised. However, we all now know coffee as being something which gives us a sense of alertness in the morning but new research at Cornell University has found that the caffeine it contains may have other effects as well.
Adenosine, a chemical widely found in nature, has receptors in sweet sensitive taste cells. These receptors are activated by internal adenosine to enhance sweet signals in the taste bud and help to promote relaxation and sleepiness.
Caffeine however, works against this receptor, so it was thought that caffeine could reduce the perception of sweet taste in humans.
To test this just over 100 people were divided into two groups. One group was given decaffeinated coffee and the other given caffeinated coffee with 200mg of caffeine in (an average coffee in the UK contains 95mg).
The participants weren’t told whether they had caffeinated or decaffeinated coffee and when asked they were unable to correctly guess which they had. They then underwent sensory testing.
In a caffeinated condition, all participants rated the sweetened coffee and any sweet solutions that followed as less sweet than the participants in the decaffeinated condition. However, the caffeine had no effect on other taste sensations such as bitterness or saltiness.
Interestingly, all participants reported feeling more alert suggesting a placebo effect of the aroma and taste of coffee regardless of the presence of caffeine. Although, reactions times didn’t change for the caffeinated or decaffeinated condition.
So, caffeine prevents us from tasting our sugar, who knew? If you’d rather taste your sugar, and I know I would, steer clear of that coffee before you indulge in that cheeky chocolate bar or delightful doughnut.