Do you prefer coffee or tea? The answer to that question might in part be down to your genes, research suggests.
Scientists say a genetic predisposition to perceiving the bitterness of particular substances appears to nudge us towards one beverage or the other. Dr Marilyn Cornelis, co-author of the research from Northwestern University in Illinois, said: “The study adds to our understanding of factors determining beverage preferences – taste, in particular – and why, holding all other factors constant, we still see marked between-person differences in beverage preference as well as the amount we consume.”
The study, published in the Scientific Reports journal, involved two sets of data. The first was a large twin study which showed that, at least in those of European ancestry, particular genetic variants are linked to the strength of perception of different tastes: one specific variant was associated with slightly higher ratings of bitterness for caffeine, another to greater bitterness for quinine and a third to greater bitterness for a drug known as propylthiouracil, or prop.
The team found people with a greater genetic predisposition to perceiving the bitterness of caffeine drank a little more coffee, but an increased perception of the bitterness of quinine and prop were linked to a small reduction in coffee drinking.
The reverse patterns were seen when the team looked at the genetic variants and how much tea participants drank.
“While the effect of perception on your daily coffee intake might be relatively small – only a 0.15 cup per day increase – from a normal caffeine taster to a strong caffeine taster, it actually makes you 20% more likely to become a heavy drinker – drinking more than four cups per day,” said Jue Sheng Ong, first author of the research from QIMR Berghofer Medical Research Institute in Australia.
The team also found that greater perception of the bitterness of prop was linked to a lower chance of being a heavy drinker of alcohol.
“Given humans generally avoid bitter tastes, we interpret these findings as possibly a learned behaviour: if we can perceive caffeine well we associate this with the psychostimulant properties of caffeine and so seek more coffee,” said Cornelis.
Ong added the findings for tea might be down to tea containing lower concentrations of bitter substances, meaning it might prove more acceptable than coffee to those with heightened perception of bitterness.
“Our taste genes partially play a role in how much coffee, tea or alcohol we drink,” he said. “The preference towards tea can be seen as a consequence of abstaining from coffee, because our genes might have made coffee a little too bitter for our palates to handle.”