36
F
Dec
2018
Feature
How taste changes over a lifetime
Infants
WHEN it comes to introducing foods to infants,
it’s important to keep trying the same foods
several times, even if they appear to dislike
it at first. Since breastmilk is sweet, many
parents start with mashed fruit. However,
starting with mashed vegetables first appears
to help them develop a taste for vegetables
sooner — and it may set up a lifelong
healthy habit. 27-29
Similarly for fussy eaters, repeated
exposure — tasting new foods 8-10 times —
is necessary before likes and dislikes
are uncovered. 27,30
To avoid a mealtime battleground,
recommend that parents add a new food
to the child’s dinner plate several nights in
a row so that it becomes familiar. Encourage
them to take a bite, but don’t fight their
reluctance. Just keep putting it on the
plate. Reading picture books about fruit
and vegetables can also help. 31
Illness
Up to 80% of people receiving cancer
treatment report changes in food flavours
affected by changes in the senses of taste,
smell and touch. 32 Treatments can interfere
with or damage sensory cells and nerves. 32
Patients undergoing radiation to the head
in Japanese.
There are three umami compounds:
monosodium glutamate (MSG); inosine-
5’-monophosphate (IMP); and guanylo-5’-
monophosphate (GMP), which stimulate umami
taste receptors.
Umami substances cause salivary secretion,
enhance appetite and increase food palatability
while also increasing satiety. 11
Headache-causing MSG has a bad
reputation, but could play a role in reducing
overconsumption of high-fat, high-sugar foods
when consumed in a pre-meal broth. 12
Umami flavours may also change brain
function, promoting healthy eating behaviours
in those at risk of obesity. 13 A miso soup before
dinner seems like a good idea.
Fat
Researchers from Deakin University and the
CSIRO have for some time been advocating for
a sixth taste sensation — fat.
They found taste receptors for fat are
linked with liking fat flavours and fat intake. 14
They also found those with impaired fat
taste sensitivity have reduced satiety after
consuming high fat foods, leading to increased
fat consumption.
Habitual high fat intake may decrease
sensitivity causing an increase in the threshold
for fat, whereas eating a low fat diet for a while
can improve fat taste sensitivity, which may
reduce overall intake. 15-17
Salty
We are unable to detect a difference in salt
taste when 10-20% of sodium is reduced,
meaning that food manufacturers can change
the sodium content of a food by this amount
before we notice it. 18,19
The Australian Government’s Healthy Food
Partnership is working on new sodium targets
for a range of foods contributing significant
sodium to the diet. 20
Salt has been found to promote passive
overconsumption of energy in adults and may
override the satiety effects that fat consumption
causes in those who are sensitive to fat taste. 21
This may be why salt and vinegar chips are
so popular.
and neck may have damage to salivary
glands, which can also effect taste.
Moisture is a necessary part of the oral
cavity so these patients will need to eat moist
foods such as stews, casseroles and soups,
and add gravies and sauces to drier meals.
A saliva replacement and/or nasal sprays
can also help.
Patients taking chemotherapy or even
prescription medications may notice odd
tastes and/or a dry mouth. Sweet foods may
taste too sweet, sensitive mouths may find
chilli or fizzy drinks overpowering whereas
others may prefer extra chilli. Adequate
nutrition aids recovery so recommend referral
to an accredited practicing dietitian if intake is
compromised. Taste changes may last for two
months once chemotherapy has ceased. 32
The elderly
Ageing can result in a reduction or loss of
taste sensitivity,33 and for elderly people
who may already have a poor appetite, loss
of taste can make achieving an adequate
diet even harder. Encourage the use of other
ingredients to flavour food such as pepper,
herbs, spices, lemon juice, vinegar, chilli,
honey and so on. Changing temperature
of foods and drinks may also help.
References on request
Bitter
A mouse study found long-term
activation of gut bitter taste receptors
resulted in weight and fat mass loss,
increased energy expenditure, enhanced
glucose tolerance and insulin sensitivity
through release of gut hormones
and suppressed inflammatory markers. 22,23
Eat those Brussel sprouts!
Sour
Adding sour ingredients such as vinegar
to carbohydrate meals can lower the glycemic
index of the meal. Sourness slows gastric
emptying and reduces post-prandial
blood glucose. 24,25
The future of nutrition therapy may
see GPs request taste tests for patients, to
determine tasting profiles for tailored dietary
recommendations and as a way to modify
risk of chronic metabolic diseases.
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