A person's
genetically fixed sense of taste, coupled with a lifetime of subtle nerve
damage, can influence dramatically his or her vulnerability to heart disease,
cancer and other afflictions, researchers report.
"This is genetic
-- what you taste determines what you like to eat," chief researcher Linda
Bartoshuk, an experimental psychologist at Yale University in New Haven,
Conn., told United Press International. "What you like to eat determines
your diet, and your diet is a risk factor for all kinds of diseases."
Some 10 years
ago, Bartoshuk and colleagues discovered the existence of what they call
"supertasters," people who "live in a neon taste world, while non-tasters
live in a pastel world," she explained. For instance, supertasters find
the thyroid medication known as PROP horribly bitter, while non-tasters
such as Bartoshuk taste nothing at all.
One out of four
people in the United States are supertasters, Bartoshuk said, adding the
percentage could be higher elsewhere. When compared to so-called non-tasters,
who also make up about a quarter of the population, super-tasters' sense
of taste is roughly three times more intense.
"Women are more
likely to be supertasters than men," she added.
Supertasters
tend to be picky eaters. Most shun foods rich in sugar and fat. They also
avoid vegetables, because they detect bitter flavors others miss. As a
result, Bartoshuk said supertasters tend to be thinner but can have a higher
risk of certain cancers.
Speaking at
the American Association for the Advancement of Science annual meeting,
Bartoshuk revealed preliminary results linking supertasting to colon cancer.
In a study of
more than 200 men, which Bartoshuk conducted with physician Marc Basson,
of Wayne State University in Detroit, the more that older men found PROP
bitter, the more likely they were to have cancerous polyps in their colons.
Colorectal cancer is the fourth leading cause of cancer-related death in
the world.
Just as with
most supertasters, these men ate fewer vegetables. However, most male supertasters
enjoy fatty, sugary foods and tend to be heavier. Eating fewer vegetables
and being heavier "are both factors for higher colon cancer risk," Bartoshuk
said, adding, "This was only seen in older men. This might be a dietary
effect that takes years to catch up."
Another study
of 2000 men with a history of ear infections found they also tended to
be heavier. Ear and upper respiratory infections such as colds all tend
to damage nerves linking the taste buds to the brain, Bartoshuk explained.
When the ability to detect flavor is inhibited, fat produces more intense
sensations. As a result, their liking and intake of fatty foods might have
increased, the results suggest, and with increased weight comes increased
risk of heart disease.
Bartoshuk said
supertasting seems to have evolved to detect poisons, which often seem
bitter, while less sensitive tongues evolved so their recipients could
grow healthier by enjoying a wider range of food.
"There are still
a lot of unanswered questions," she noted. For example, it is unclear why
some male supertasters prefer sugary, fatty foods while others do not.
Also, when women experience similar nerve damage, their dislike of fatty
foods tends to intensify.
In terms of
health benefits, Bartoshuk pointed out medications are under development
to make bitter foods more palatable, so everyone can enjoy the health benefits
of foods such as vegetables.
"The future
is very rosy in term of our ability to inhibit bitterness," she explained.
Ethnobotanist
Timothy Johns, of McGill University in Toronto, found Bartoshuk's work
"enriching. Now we need to further explore the whole idea of diversity."
Bartoshuk hopes
researchers one day can understand more clearly the taste sensitivity levels
in the rest of the world. Although some studies suggest Asians have more
supertasters, she said, little remains known about African or Hispanic
populations.
--
Copyright 2003 by United
Press International.
All rights reserved.
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