intakes of Beverages - by
Popkin et al. American Journal Clinical
Nutrition 2006; 83:529-42
|Tea, coffee (unsweetened)
|Low fat milk and
sweetened soft drinks
| - fruit juice, vegetable
juice, full fat milk, sports drinks
| - alcoholic
0-2 drinks/day for men
human body can last weeks without food,
but only days without water. The body is
made up of 55 to 75 per cent water. Mature
adults are about 70% water; this drops to
about 60% in the elderly and continues to
drop into very old age. Water forms the
basis of blood, digestive juices, urine
and perspiration. The water content of the
body breaks down along these lines:
· 80 per cent of blood is made up
· 73 per cent of lean muscle (including
brain tissue) is water
· 25 per cent of fat is water
· 22 per cent of those solid-looking
bones are water.
The body is unable to store water for any
length of time and needs fresh supplies
every day due to losses from lungs and skin,
accounting for 50% of water loss; losses
from urine and faeces account for the rest
of the total losses. The amount we need
depends on our metabolism, the weather,
the food we eat and our activity levels.
Heavy or obese people carry less body water
than people of a healthy weight. As fat
content increases, lean tissue decreases,
leading to an overall decline in total body
water. Body water is higher in men than
in women and falls in both with age. Most
mature adults lose about 2.5 litres (women)
to 3 litres (men) per day and the elderly
lose about 2 litres per day. This water
loss needs to be replaced through food and
beverages. Foods provide about 1 litre of
fluid and the remainder must be obtained
Water is needed in the body to:
1. Maintain the health and integrity of
every cell in the body.
2.Keep the bloodstream liquid enough to
flow through blood vessels.
3.·Help to eliminate toxins (such
as those found in tea, coffee, alcohol,
refined foods and soft drinks) through urine
4.Regulate body temperature through sweating.
5.Keep mucous membranes moist, such as those
of the lungs and mouth.
6.Lubricate and cushion joints.
7.Reduce the risk of cystitis by keeping
the bladder clear of bacteria.
8.Aid digestion and prevent constipation.
9.Work as a moisturiser to improve the skin's
texture and appearance.
10.Carry nutrients and oxygen to cells.
11.Serve as a shock absorber inside the
eyes, spinal cord and in the amniotic sac
surrounding the foetus in pregnancy.
mild dehydration and poor fluid intake can:
1.Increase the risk of kidney stones and
2.Increase the risk of urinary tract cancers
3.Increase the risk of breast and colon
4.Increase the risk of childhood obesity
5.Diminish physical and mental performance
6.Diminish salivary gland function
a normal day, the body loses 2.4 litres
of water (or 10 cups) and this figure is
higher on warmer days, or when exercising.
When the water content of the body drops
below optimal levels, the result is dehydration.
This is easily remedied by increasing fluid
intake. Mild dehydration is often observed
because many people do not consume enough
fluids. About 30-40% of Australians were
having less than 6-8 cups of fluid on the
day of the Nutrition survey conducted in
for dehydration include headaches, lethargy,
mood changes and slow responses, as well
as dry nasal passages, and dry or cracked
lips. Other symptoms of dehydration include
dark-coloured urine, weakness, tiredness,
confusion and hallucinations. Eventually
urination stops, the kidneys fail and toxic
waste products can't be removed by the body.
In extreme cases, this may result in death.
at most risk of dehydration are the elderly
and children. It can also be an issue for
people travelling on aeroplanes. A traveller
can lose approximately 1.5 litres of water
during a three hour flight.
The various causes of dehydration include:
Increased sweating due to hot weather/humidity,
2. Lack of drinking water
3. Insufficient signalling mechanisms in
the elderly; sometimes they do not feel
thirsty even though may be dehydrated
Increased output of urine due to a deficiency
of pituitary or adrenal hormones, diabetes,
kidney disease, or medications that increase
the output of urine like diuretic drugs
for the treatment of high blood pressure.
5. Increased output of faeces (diarrhoea)
or vomiting due to illness such as cholera,
dysentery, food poisoning
6 . Recovering from burns
function can decline as part of the normal
ageing process with decrease in kidney mass.
This together with hormonal changes and
factors such as decreased thirst perception,
medication, cognitive changes, limited mobility,
and increased use of diuretics and laxatives
can increase their risk of dehydration or
decrease their requirement for fluid. It
is estimated that 6 household glasses or
cups (at least 150millilitres each) in combination
with an adequate intake of food will provide
more than the required 2 litres a day in
a temperate climate. Although healthy older
Australians living independently appear
to drink sufficient fluid their risk of
dehydration increases with medication use,
chronic illness and frailty.
Children are very susceptible to dehydration,
particularly if they are ill. Vomiting,
fever and diarrhoea can quickly dehydrate
a baby. This can be a life threatening condition.
If you suspect dehydration, take the child
immediately to the nearest casualty department.
Some of the symptoms of dehydration in a
· Cold skin
· Dry mouth
· Depressed fontanelle on the skull
· A blue tinge to the skin as the
water requirements are observed :
1. for people consuming a high protein diet
because it requires more water for digestion
and removing nitrogen from protein
2. for people consuming high fibre diets
- fluids are important in preventing constipation
especially if wholemeal or wholegrain foods
are consumed in large amounts.
3. for Children
4. during episodes of vomiting and/or diarrhoea
5. during physical activity
6. when exposed to warm/hot conditions
The kidneys regulate the amount of water
in the body. A special gland in the brain
called the hypothalamus monitors water levels.
If there is too little water in the body,
the hypothalamus asks the nearby pituitary
gland to communicate the need to conserve
water to the kidneys. This is achieved by
the secretion of a chemical called antidiuretic
hormone. Once the kidneys receive this message,
they reabsorb more water and concentrate
the urine. At the same time, we are prompted
to drink by the sensation of thirst, which
is signalled by the brain. Alternatively,
if there is too much water in the body,
the hypothalamus instructs the kidneys -
via the pituitary gland - to dilute the
urine and get rid of the excess.
Drinking too much water can also damage
the body. If too much water is consumed,
the kidneys cannot excrete enough fluid.
Water intoxication can lead to headaches,
blurred vision, cramps and eventually convulsions.
For water to reach toxic levels in the body,
an individual would have to consume many
litres a day. Water intoxication is most
common in people with particular diseases
or mental illnesses (for example, in some
cases of schizophrenia), and in infants
who are fed high quantities of fluid with
low electrolyte levels (for example, infant
formula which is too diluted).
Many people believe that drinking water
causes fluid retention. In fact, the opposite
is true. One of the main causes of fluid
retention is a high concentration of sodium
(salt) in the body. Drinking water helps
the body rid itself of excess sodium - this
results in less fluid retention. The body
also retains fluid if there is too little
water in cells. If the body receives enough
water on a regular basis, there will be
no need for it to conserve water - and this
will reduce fluid retention.
content in food
Most foods, even those that look hard and
dry, contain water. Generally, the higher
the water content, the lower the kilojoule
count. Uncooked meat is two thirds water;
most fruits are many vegetables are 90 percent
water. The body can get about half of its
water needs from food alone. The digestion
process also produces water as a by-product
and can provide around 10 per cent of the
body's water requirements. The rest can
come from liquids.
water contains salt
Commercially bottled mineral water typically
contains spring water, salts and carbon
dioxide. The sodium in mineral water can
lead to fluid retention and swelling. It
can even increase blood pressure in susceptible
people. It is advisable to limit the amount
of mineral water in the diet, or at least
make low sodium varieties your preference.
The label should state less than 30mg sodium
per 100ml, or 300ppm (parts per million).
Mineral waters that are sweetened and flavoured
are more or less equivalent to regular soft
drinks as far as kilojoule content and artificial
additives are concerned.
much water/fluids are recommended daily?
has become a common belief that we need
"2 litres or 8 glasses" of water
daily and that beverages containing caffeine
or alcohol do not count because they increase
the excretion of water or have a diuretic
effect. This belief has never been scientifically
tested, and there is little evidence to
support it. A recent review of the evidence
was published in the American Journal of
Physiology: Endocrinology and Metabolism
(August 2002) http://ajpregu.physiology.org/cgi/content/abstract/00365.2002v1.
The review found that such a large amount
of liquid is not needed because diet surveys
with thousands of adults have shown that
many adults did not consume this much fluid
and were still considered to be healthy
and not dehydrated. Also, the system that
regulates water balance is precise. The
review concluded that some people may need
large amounts of fluids, particularly if
they are physically active and in hot climates
and that caffeine and alcohol containing
beverages can be counted as "water"
because most of the water in these beverages
does get used by the body.
how much water is recommended daily? Approximately
six to eight glasses (of at least 150 millilitres
each) of a variety of "fluids"
can be consumed each day.
than eight glasses may be needed for the
physically acitive, for children, for people
in a hot/humid environments and for breastfeeding
women (who need an extra 750-1000ml per
water may be needed by the sedentary, for
the elderly, for people in a cold environment,
or if many high water content foods are
includes fresh water and all other liquids
like juice, soft drinks, coffee, tea, milk,
soup. Fresh water is the best drink of all
because it does not contain calories and
has fluoride that is good for the teeth.
The next most important fluid is milk (especially
for children) and tea (especially for adults).
Tea, especially green tea, is an important
source of antioxidant polyphenols which
appear to offer protection against heart
disease and cancer. However, the additional
energy from milk and sugar added to tea
can be substantial in some people. Fresh
fruit is preferable to fruit juice because
the former has more fibre and nutrients
and less sugar; for these reasons it is
recommended that juice consumption be limited
to one to two glasses a day. Soft drinks
and other sweet drinks with added sugar
should be limited because they add substantial
dietary energy to the diet without additional
Healthy Beverage Pyramid for adults was
created by Dr John Weisberger of the American
Health Foundation. The guide follows the
same principles as related Healthy Eating
Pyramids (please note: 1 glass in this pyramid
MOST of the drinks featured at the base
of the Pyramid (this means water, 3-4 glasses
MODERATELY of the drinks featured in the
second tier of the Pyramid (tea and/or vegetable
soup, 2-3 glasses a day)
MODESTLY of the drinks featured in the third
tier (milk, juice, coffee 1-2 glasses a
LEAST, if at all, of the drinks at the tip
of the Pyramid (this means red wine, 0-1
glasses a day)
pyramid provides a minimum of 6 OR a maximum
of 10 glasses of fluid a day.
The added advantage of choosing a variety
of fluid is that a variety of nutrients
will be consumed. For example vitamin C
(juice), antioxidants (from tea, juice and
wine), potassium and other minerals (juice
and soup), folate (tea and juice) and calcium
(milk). The fluid pyramid guidelines were
designed to moderate the intake of sweetened
drinks such as soft drinks, cordial and
sports drinks to encourage responsible alcohol
consumption and to limit caffeine intake.
Since the pyramid was designed for adults,
children would switch milk for tea/coffee
and have no alcohol.
of the literature and evidence on which
the Dietary Guidelines for Australians
are based 2001
(Australian -Victorian Government website)
Updated: June 2006