Water in the diet
Water is essential for life. It is required for digestion,
absorption and transportation, as a solvent for nutrients, for elimination of
waste products and to regulate body temperature. Water is constantly lost from
the body and needs to be replaced.
| Water |
Water requirements vary with age and at some life stages. Water
turnover is higher in infants and young children than in adults. Breast milk or
infant formula should be the main drink in the first 12 months. Exclusively
breastfed infants do not require additional fluids up to 6 months of age. For
formula-fed infants, cooled boiled tap water may be used if additional fluids
are needed from birth. From around 6 months, small amounts of cooled boiled
water can supplement breast milk.
Pregnant and breastfeeding women have a slightly increased
water requirement compared with other women because of the needs of the fetus
or baby and other changes that occur in the body during pregnancy and
lactation.
Older people can experience dehydration if they have an
inadequate intake of water or other drinks. The normal decline in kidney
function with age, plus hormonal changes, decreased perception of thirst, some
medications, cognitive changes, limited mobility and increased use of diuretics
and laxatives may lead to reduced hydration in older people. These changes may
be normal adaptations of the ageing process but the outcomes of dehydration in
the elderly are serious and include cognitive impairment, functional decline,
falls or stroke.
How much water is needed?
Adequate fluid consumption is an integral component of a
healthy diet. Water is a good source of fluids and has the advantage of not
adding energy to the diet. The NHMRC Nutrient Reference Values 14 contain
guidance on the intake of water that can be consumed over the course of a day.
However there is no single recommended intake, as water requirements at any one
time will vary depending on climate, physical activity, body surface area and
individual metabolism. Total water requirements include the water content of foods
as well as fluids.
The following intakes can be used as a general guide for
fluids: about 4-5 cups of fluids a day for children up to 8 years, about 6-8 cups for adolescents, 8
cups for women (9 cups in pregnancy and lactation) and about 10 cups for men.
It is preferable to meet most fluid needs by drinking plain
water. Many commonly consumed fluids such as tea and coffee provide water,
although large quantities can have unwanted stimulant effects in susceptible
people. Tap water is an ideal option because it is inexpensive and meets high
palatability and hygiene standards.14 most tap water in most parts of the world
is fluoridated, which has been shown to be a safe and effective public health
measure. Fluoridation of tap water provides an additional benefit for
development of strong teeth and bones, making it a good choice to ensure
adequate hydration.
Sources of water include;
- Drinks of all kinds.
- Foods, such as fruits and vegetables, meat, eggs.
- Combustion or oxidation - when fats, carbohydrates and protein are used for energy, a certain amount of water (metabolic water) is produced within the body.
| Woman drinking juice |
