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Coffee: overcoming our natural defenses

Written by Tristan Free (Digital Editor)

The bitter taste of caffeine should be a warning sign not to drink coffee. So why do so many of us start the day with a hot cup of Joe?7118

Bitter taste is the result of evolution, a warning for harmful or toxic substances. So why do people still drink and enjoy coffee? Well a recent study led by Marilyn Cornelis, of Northwestern University (IL, USA), has uncovered a link between taste sensitivity and coffee consumption. The research team found that, contrary to expectations, the higher a person’s sensitivity to the bitter taste of caffeine, the more coffee they drank.

The research team used Mendelian randomization to test the relationship between bitter taste sensitivity and beverage consumption in a cohort of over 400,000 men and women in the UK. Previous genome-wide analysis of solution taste ratings from two Australian twins was used to establish the genetic variants linked to taste perception of 3 different sources of bitterness; caffeine, quinine and PROP. These genetic variants were then compared against self-reported tea, coffee and alcohol consumption.

The results showed that as the sensitivity to the bitterness of caffeine increased, so did the consumption of coffee. This correlation suggests that as a consumer acquires the ability to detect the caffeine, which they associate with a positive reward, they learn to enjoy the coffee. Therefore, those that are more capable of detecting the caffeine are more likely to enjoy and drink more.

Meanwhile, the study also showed that those sensitive to the bitterness of quinine and PROP largely avoided coffee, and an increased sensitivity to PROP indicated a decreased affinity for alcohol, particularly red wines. “The findings suggest our perception of bitter tastes, informed by our genetics, contributes to the preference for coffee, tea and alcohol,” concluded Cornelis.

These results shed light on the mechanics of taste, a sense that is often overlooked in terms of importance and research, and takes a step towards forming a better understanding of the biology that controls and informs our preferences.