New findings show that people may
be genetically predisposed to love the taste of certain beverages. Furthermore,
this biological discovery could have far-reaching health consequences.
Evolution is
thought to have favored people who were able to sense bitterness.
After all,
sharp and unpleasant tastes can often come from toxic substances such as
alkaloids that are present in poisonous plants.
But scientists
have been confounded by the popularity of coffee for
some time.
Coffee's
bitter taste should theoretically elicit a negative response from people, and
yet the drink is one of the most widely consumed beverages in the world.
The
researchers behind a new study believe they may have found why humans enjoy
drinking coffee, despite its bitterness.
Scientists
from Northwestern University Feinberg School of Medicine in Chicago, IL, and
QIMR Berghofer Medical Research Institute in Australia teamed up to examine the
relationship between a person's genetic sensitivity to bitter substances, and
the level of bitter beverages they consume.
How our taste
works
"Taste
has been studied for a long time, but we don't know the full mechanics of
it," says Marilyn Cornelis, assistant professor of preventive medicine at
Northwestern University. "Taste is one of the senses. We want to
understand it from a biological standpoint."
The study by Cornelis and colleagues uses
two sets of data, and they have published it in the journal Scientific Reports. The first dataset came from a large-scale study of Australian
twins that showed a link between genetic variants and how people perceived
different tastes.
Researchers highlighted specific variants they believed to be
responsible for a higher perception of bitterness in three substances:
caffeine, quinine, which is an ingredient in tonic water, and PROP, which is
another bitter compound present in some vegetables.
The second
dataset came from the UK Biobank, a research facility that stores blood, urine,
and saliva samples from hundreds of thousands of people. The research team used
more than 400,000 male and female samples along with self-reported answers from
a questionnaire about beverage consumption.
The study used
a natural experimental method called Mendelian randomization to compare
variants in people's genes with how often the same people drank coffee, tea,
and alcohol.
The definition
of a heavy coffee drinker was someone who drank more than 4 cups a day while
heavy tea drinking was more than 5 daily cups. Heavy alcohol drinkers were
deemed to be those who drank more than three or four times each week.
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