New York, November 18 (IANS): Are you a tea or coffee person? The answer may lie in their genetic predisposition to bitter tastes, researchers say. It may be because bitterness acts as a natural alert system to protect us from harmful substances. The study, led by researchers at Northwestern University and the QIRO Berghofer Institute of Medical Research in Australia, explored reactions to three bitter substances – caffeine, quinine and propylthiouracil (PROP) – to understand how they affect people's preference for drinking tea , coffee. and alcohol.
The results showed that people who were more sensitive to caffeine and drank too much coffee consumed small amounts of tea. In other words, people who have a greater ability to feel the bitter taste of coffee – and particularly the distinct bitter taste of caffeine – learn to associate "good things with it."
"You would expect people particularly sensitive to the bitter taste of caffeine to drink less coffee," said Marilyn Cornelis, assistant professor of preventative medicine at Northwestern University's Feinberg School of Medicine. "The opposite results from our study suggest that coffee consumers acquire a taste or ability to detect caffeine because of the positive reinforcement learned (stimulation) caused by caffeine." The study, published in the journal Scientific Reports, also found that people sensitive to the bitter flavors of quinine and PROP a synthetic taste related to the compounds in cruciferous vegetables avoid coffee. For alcohol, a greater sensitivity to the bitterness of PROP resulted in lower consumption of alcohol, particularly red wine.
"The findings suggest that our perception of bitter tastes, informed by our genetics, contributes to our preference for coffee, tea and alcohol," said Cornelis. Scientists applied Mendelian randomization, a technique commonly used in disease epidemiology, to test the causal relationship between bitter taste and consumption of beverages in more than 4,000,000 men and women in the UK.