Washington DC: You might be a coffee lover, but you can't deny that the beverage has a bitter taste to it. It turns out, the more sensitive people are to the bitter taste of caffeine, the more coffee they drink.
Why do we like the taste of coffee? While logically, we should want to spit it out because of the bitterness.
"You'd expect that people who are particularly sensitive to the bitter taste of caffeine would drink less coffee. The opposite results of our study suggest coffee consumers acquire a taste or an ability to detect caffeine due to the learned positive reinforcement (i.e. stimulation) elicited by caffeine," said Marilyn Cornelis, lead researcher of the study.
In other words, people who have a heightened ability to taste coffee's bitterness, and particularly the distinct bitter flavour of caffeine, learn to associate good things with it. The study was published in the journal of Scientific Reports.
The study found that people sensitive to the bitter flavours 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," Cornelis said.
As part of 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.
"Taste has been studied for a long time, but we don't know the full mechanics of it. Taste is one of the senses. We want to understand it from a biological standpoint," said Cornelis.
