Who does not enjoy a delicious cup of coffee?
However, humans should not enjoy the bitter flavor. Scientists believe that animals evolved the ability to detect bitter tastes in order to avoid harmful or poisonous substances.
Could it be that coffee drinkers are less sensitive to bitter flavors?
That would make sense, but the opposite is actually true. A team of international researchers reported in 2018 that those who are more sensitive to the bitter taste of caffeine tend to consume more coffee. The scientists utilized a large genetic database containing information from over forty thousand individuals. They examined three genetic variants known to cause sensitivity to quinine, propylthiouracil, and caffeine, all of which are bitter substances. A questionnaire survey revealed that individuals with the genetic variant that made them sensitive to the bitterness of caffeine tended to consume more coffee.
Nevertheless, if sensitivity to bitter taste evolved to detect and avoid poison, why do people who are more sensitive to the bitter taste of caffeine prefer coffee?
Scientists believe that learned conditioning may be the explanation. People who are more sensitive to the bitter taste of caffeine may be able to associate that taste with the stimulating effects of caffeine more readily. Caffeine is the most widely used psychostimulant in the world.