Bitterness is natural warning system to protect us from harmful substances, so we really shouldn't like coffee. Scientists say people with heightened ability to detect coffee's bitterness learn to associate good things with it.
The more sensitive people are to the bitter taste of caffeine, the more coffee they drink, reports a new study from Northwestern Medicine and QIMR Berghofer Medical Research Institute in Australia. The sensitivity is caused by a genetic variant.
In this study population, people who were more sensitive to caffeine and were drinking a lot of coffee consumed low amounts of tea. But that could just be because they were too busy drinking coffee, a researcher noted.
The study also found people sensitive to the bitter flavors of quinine and of PROP, a synthetic taste related to the compounds in cruciferous vegetables, avoided coffee. For alcohol, a higher sensitivity to the bitterness of PROP resulted in lower alcohol consumption, particularly of red wine.
"The findings suggest our perception of bitter tastes, informed by our genetics, contributes to the preference for coffee, tea and alcohol," researchers said.
For the study, scientists applied Mendelian randomization, a technique commonly used in disease epidemiology, to test the causal relationship between bitter taste and beverage consumption in more than 400,000 men and women in the United Kingdom.
The genetic variants linked to caffeine, quinine and PROP perception were previously identified through genome-wide analysis of solution taste-ratings collected from Australian twins. These genetic variants were then tested for associations with self-reported consumption of coffee, tea and alcohol in the current study.