Water: Water is defined as an essential nutrient because it is required in amounts that exceed the body’s ability to produce it. All biochemical reactions occur in water. It fills the spaces in and between cells and helps form structures of large molecules such as protein and glycogen. In human adults total body water accounts for about 70 per cent of the lean body mass.
Distribution: In an adult male of 70 kg body weight, 70, percent of water that is 30 litres is
found in intracellular fluids. Of this about 4 litres are found in bones. The
remaining 30 percent of water is extra cellular fluid found in 3 litres of
plasma and 8.5 litres of intersti-tial fluid and one litre of transcel-lular
fluid which includes saliva, pancreatic juice, aqueous humor and cerebrospinal
Functions: Water performs the
fol-lowing functions in the body
Controls body temperature
Transports nutrients and waste
Dissolves important substances in tissues and cells
Lubricate the cushion joints
Protect the spinal cord and other sensitive tissues
Get rid of wastes through uri-nation, perspiration, and bowel
Requirements: the requirement of water depends on
person’s age, weight and life style. Adults should consume 1 litre of water for
every 1000kcal in their diet, infants should consume 1.5 litre/1000kcal.
Overall water balance: The aver-age adult
processes 2.5 litres to 3 litres of water each day.
Water enters the body in three forms:
Water taken in as water or in other beverages
Preformed water in food
Metabolic water produced by cell oxidation
Water leaves the body in the follow-ing ways
• Kidneys Skin
• Lungs Faeces
Water imbalance: Water can be depleted in the body due to reduced intake caused by unavailability of
water, inability to obtain water and swallow it. Increased losses of water are
also experienced due to hot environment, hyperventilation, pro-longed vomiting
and diarrhea, kidney dis-orders and diabetes insipidus.
Water deprivation: Dehydration of body occurs when water is not taken in adequate amounts to
make up for the water loss. It occurs in severe diarrhea and vomiting.
Evi-dence of dehydration manifests in the form of sunken eyes, dry tongue,
loose and inelastic skin. Simple water deprivation also causes loss of sodium
and potas-sium. The subject should be given water, glucose and electrolytes to
replenish his fluid levels.
Water Intoxication (water excess): Over hydration occurs when large quantities of water are drunk
in a hot climate or water excretion by the kidneys is impaired. Water Excess
causes drowsiness, giddiness confusion headache, nausea, con-vulsions and coma