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t_Articles
"Let's face it: Food is one of life's great and
dependable pleasures. If we eat well in the sense of flavor and
pleasure, we will also eat well in terms of health."
Barbara Kafka, The Opinionated Palate
Each of us has a personal range of foods we enjoy. It
could be the smooth taste of chocolate, the unique taste of durian or
the spiciness of a good curry. Our preferences for some foods over
others result from a complex interplay among many factors including
genetics, age, early food experiences, ethnic customs, pleasantness of
surroundings when trying a new food and physiological reactions to a
food.
One thing is clear - the flavour of foods is a most
compelling influence in shaping our food choices. Research from the
United States, (Food Marketing Institute, 1998) shows that people rank
taste as the number one reason for selecting foods, with nutrition
ranking second. And while people are attuned to nutrition messages, they
often fear that eating a more healthful diet means giving up favourite
foods. Nutrition communicators can combat these fears by assuring people
that healthful and delicious eating can go hand in hand.
More to taste than meets the tongue
What we commonly call the "taste" of food is really "flavour",
resulting from the interaction between the senses of taste and smell.
Other sensations from foods, such as the burn of a chilli, the bite of a
strong peppermint or the fizz of a carbonated drink, as well as texture,
temperature and appearance all add to the flavour experience.
As much as 80 percent of what we perceive as taste is
actually smell. Humans can discern about 20,000 different odours and ten
intensities of each. Smell occurs when the odours reach the olfactory
receptors in the nasal cavity via two routes - inhalation through the
nostrils and through the back of the mouth as we chew and swallow.
True taste occurs on the tongue. We are born with
10,000 taste buds located on the back, sides and the tip of the tongue,
on the palate and in the throat. When taste receptor cells within the
taste buds are excited by chemical stimuli, they detect five primary
sensations: sweet, sour, salty, bitter and "umami", the savoury taste of
glutamate found in protein foods and monosodium glutamate (MSG). Each
taste is sensed throughout the tongue, though we experience some tastes
more prominently in certain areas. For example, sweet tastes are more
pronounced on the tip of the tongue, while sour tastes are experienced
to a greater extent on the sides.
Taste changes through the ages
Our first flavour experiences are sweet ones, said Dr
Gary Beauchamp, Director of the Monell Chemical Senses Center,
University of Pennsylvania, USA. "A variety of tastes and odours are
transmitted through amniotic fluid to the foetus," said Beauchamp.
"Unborn infants appear to detect sweetness and newborns clearly sense
and enjoy sweet tastes."
Infants seem to experience the other primary tastes
to varying degrees. The ability to detect bitter, salty and umami tastes
continues to develop throughout the first few months of life. The sour
taste is at least somewhat developed at birth but it's not clear whether
further changes occur as infants get older.
Breast-fed infants receive early exposure to a
variety of flavours because breast milk carries the flavour of foods and
spices eaten by the mother. Whether these and other early taste
experiences affect food preferences later in life is the subject of
ongoing research at the Monell Center.
Taste Tidbits
- Taste buds first appear when a foetus is seven or eight weeks old
and are functioning by the third trimester of pregnancy.
- When children turn their noses up at spinach and ask for sweets,
perhaps Mother Nature is to blame. Sweet foods in nature, such as
mother's milk and fruit are rich in the calories infants and children
need for growth. Extremely bitter planst and berries may be a warning
of a poisonous plant.
- Ever wonder why you can't tast food when you have a cold? It's
because the cold dulls your sense of smell, which is largely
responsible for taste perception.
- Burning your tongue kills some taste buds but the regenerate
within a few months.
- The taste "umami" means "deliciousness" or "wonderful taste" in
Japanese. Umami is the taste effect of monosodium glutamate (MSG),
which is described as brothy, meaty and savoury.
Taste declines with age
At about age 60, even healthy people begin to
experience a modest decline in taste and more dramatic declines in
smell. "Taste and smell changes in the elderly result from normal aging,
medications, certain illnesses such as Alzheimer's disease, radiation
therapy and even environmental factors such as pollution," according to
Susan Schiffman, Professor of Medical Psychology at the Duke University
Medical Center in Durham, North Carolina, USA. "It's difficult to
separate out an exact cause of these declines."
Dulled taste and smell often result in a waning
appetite, which puts the elderly at risk of malnutrition, weight loss
and increased susceptibility of disease. "Amplifying food flavours for
older people can enhance their appetites and help improve their
nutritional and immune status," said Schiffman. She suggests using fruit
juices, spices and herbs to increase food flavours.
Super taster
When your child, patient or co-worker balks at eating
spinach or broccoli, put it down to bad taste. You may be dealing with a
"super taster" whose taste buds are highly tuned into - and turned off
by - bitter compounds found in foods such as pungent vegetables,
grapefruit juice, wine, green tea and strong coffee.
"About 25 percent of the population are genetically
programmed to be super tasters who sharply detect bitter compounds in
food," said Dr Adam Drewnowski, Director of the Nutritional Sciences
Program at the University of Washington, Seattle, USA, and an expert on
taste and food choices. "Half of the population detects these compounds
to some degree and another 25 percent don't detect them at all."
What makes super tasters so bitterly sensitive to
foods? Compared to their less discriminating colleagues, super tasters'
tongues are packed with many more fungiform papillae, the little bumps
on the tongue that house the taste buds. About two-thirds of super
tasters are female and the sensitivity often fades with age. One theory
is that, in years gone by, super tasting served as a survival mechanism.
"Perhaps the characteristic discouraged pregnant women from eating
poisonous plants or berries, which tend to taste bitter," said
Drewnowski.
Ironically, many of these bitter substances are
disease-fighting phytochemicals that may be beneficial to health. Super
tasters can help the vegetables go down and optimise nutrient intake by
adding a little oil or margarine to their dish. According to Drewnowski,
fat improves the flavour of vegetables by masking the bitter taste.
Are You a Super Taster?
Try this test to see whether you're a super taster.
Using a hole punch, punch a hole in the middle of a
5-cm square of waxed paper (lunch wrap). Place the hole on the tip of
your tongue. Swab some blue food colouring on the exposed part of the
tongue and, using a magnifying glass and a flashlight, count the number
of fungiform papillae (the pinkish circles). Super tasters will have
dozens of papillae; non-tasters will have only five or six.
Tasteful recommendation
"If a food doesn't taste good, people are unlikely to
eat it," says nutritionist/dietitian Julie Howden, of the Asian Food
Information Centre. "Not everyone likes the same foods or tastes a
particular food in the same way." It's therefore important for
dietitians to work with an individual's personal food preferences when
counselling. "For instance, show them how to fit a favourite dish that's
higher in fat, sodium or sugar, into a healthful meal plan, rather than
automatically cutting it out of the diet," says Howden.
Effective nutrition counselling involves the art of
balancing individualised nutrition advice with health needs, lifestyle
factors and taste preferences. Keeping food pleasure at the forefront is
an essential ingredient for lasting success.
Taste Tips, Tricks and Techniques
Nutrition counsellors can maximise the effectiveness
of their advice by incorporating the following suggestions:
- Plan meals that include a wide palette of colours and shapes for
eye-appeal and a variety of textures and temperatures for tongue
appeal.
- Increase food flavours by adding small amounts of intense-flavoured
ingredients such as tasty cheese, toasted nuts or sesame seeds.
- Encourage older adults to alternate between bites of food with
different tastes, temperatures and textures.
- Try milkshakes made from coffee or chocolate extracts to mask a
bitter taste from medication.
- Be adventurous! Expand your tastes to enjoy a variety of foods.
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