Science Proves That We Shouldn’t Like Coffee – But Why Do We?


If you’re a coffee lover, you know that drinking coffee is a usually complex and nuanced experience. A few of the many things that draw an individual to coffee usually includes it’s rich aroma, comforting warmth, and the loveliness of the ritual of sitting down with a fresh cup as you wake up in the morning. However, if you focus on the actual taste of coffee on your tongue, there’s no getting around the fact that it’s usually quite bitter, and bitterness isn’t always the most appealing or sought taste.

Though, it turns out, the more sensitive people are to the bitter taste of caffeine, the more coffee they drink, reports a brand new study from Northwestern Medicine and QIMR Berghofer Medical Research Institute in Australia. According to Northwestern Medicine and QIMR Berghofer Medical Research Institution, coffee lovers aren’t less sensitive to the bitter taste; as you might have guessed, they’re actually more sensitive to it, which had lead to a deeper research into the psychological reasoning behind the love for coffee – and the addiction it could cause. So, why do we like the bitter taste of coffee? Bitterness evolved as a natural warning system to protect the body from harmful substances. By all means, we should in theory want to immediately spit it out.

“You’d expect that people who are particularly sensitive to the bitter taste of caffeine would drink less coffee,” said senior author Marilyn Cornelis, assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine. “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.” Cornelis then continued,  “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.”

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, Cornelis noted.

The study also discovered that those people who are sensitive to the bitter flavours of quinine and of PROP, a synthetic taste related to the compounds in cruciferous vegetables, generally 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. Though, interestingly enough, the study also found another discovery while researching other bitter tastes in tea and alcohol – the fact that coffee drinkers consume less tea. However, according to Cornelis, it is likely purely because they’re drinking more coffee instead.

For the study, scientists applied Mendelian randomisation, 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,” Cornelis said. “Taste is one of the senses. We want to understand it from a biological standpoint.”

A recent report in Molecular Nutrition and Food Research by a group of scientists from Rome also explored the possibility that coffee’s addictive properties also involve the brain’s marijuana-like neurotransmitter system. The idea was first touched on when Scientists first discovered that coffee stimulates the release of the neurotransmitter dopamine which produces the euphoria and pleasant feelings that people often associate with their first cup of coffee in the morning. Interestingly, many drugs that produce euphoria, such as cocaine, amphetamine and ecstasy.

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