A study  by QIMR Berghofer Medical Research Institute and PhD student Jue Sheng Ong, published in the journal Scientific Reports on Friday, showed the choice between coffee and tea and how much a person consumes was thanks to their genetics.

The study analysed bitter-taste-perception genes using data from more than 400,000 people.

A person’s perception of bitterness, which was determined by their genes, could dictate if they preferred coffee or tea and if they drink a lot or little.

The study showed light coffee drinkers were classified as those who drank fewer than two cups a day, while heavy coffee drinkers drank more than four cups.

Heavy tea drinkers were classified as those who drank more than five cups a day.

The Australian Bureau of Statistics data showed 46 per cent of the Australian population
consumed coffee, including coffee substitutes, while 38 per cent of Australians drank tea.

The ABS stated that the median daily consumption by coffee drinkers was 330 millilitres, which was equivalent to a large mug.

Meanwhile, the median daily amount of tea consumed by tea drinkers was 400 millilitres, which was equivalent to about two small cups.

Mr Ong said the study found people with certain genes were able to taste the varied types of bitterness in either caffeine, certain vegetables or quinine preferred different beverages.

“Coffee, tea and alcohol are widely consumed drinks that have a bitter taste and have been found to
have beneficial and adverse health effects," he said.

“We identified that people who tasted the bitterness in caffeine were more likely to love coffee and
drink more of it."

Mr Ong said people who were less able to taste the bitterness did not enjoy coffee as much.

“On the other hand, if you were genetically predisposed to taste the bitterness in brussels sprouts,
then you were more likely to prefer a cup of tea to coffee," he said.

“The results were similar for other vegetables high in the compound propylthiouracil (PROP), such as broccoli.

“The same was true for red wine, with people who didn’t like PROP-rich foods also less likely to pour
themselves a glass of red.

“That’s probably because red wine shares similar compounds to those vegetables.

“This study provides some answers about why certain people are at higher risk of heavy
consumption of these bitter drinks.”

In the study, Mr Ong also compared people with those genes in relation to their alcohol consumption as well as their coffee and tea intake.

The study showed heavy alcohol consumption was defined as drinking more than three to four times a week.

QIMR Berghofer’s Statistical Genetics research group associate Professor Stuart
MacGregor said showing the link between taste perception and consumption could have implications for future research.

“It improves our understanding of people who are big drinkers of alcohol or coffee and opens the
door to new research into treatments,” he said.

“It also sheds some light on nutrition in general.

“We know that there are lots of factors that affect how and why people drink certain things, but
this study highlights the importance of taste genetics on our drinking habits."

Mr MacGregor said they were now looking to further develop the study's findings to evaluate if bitter taste genes could have implications on disease risks.

He said the study would also explore the genetic basis of other taste profiles such as sweet and salty.

The study was a collaboration with Northwestern University’s Feinberg School of Medicine in the
United States.