Human Nutrition 3(3+0)
Lesson 45 : Water Functions and Water Balance


In the human body water performs the following functions:

  • regulates body temperature
  • carries nutrients throughout the body
  • improves digestion
  • eliminates waste and toxins from the body

Water makes up two-thirds of the human body and is essential for life. Water helps the body to maintain a constant temperature by acting as a thermostat. When a person is in a hot environment, the body sweats, and when the sweat evaporates, it lowers the body temperature and restores homeostasis.

As a solvent water delivers many nutrients to cells, while it also helps the body eliminate waste products from the cells. Both the spaces between cells (intercellular spaces) and the spaces inside cells (intracellular spaces) are filled with water. Water lubricates joints and acts as shock absorber inside the eyes and spinal cord. Amniotic fluid, which is largely water, protects the fetus from shock.

Water is an important vehicle for ridding the body of waste products in the form of urine.

Last modified: Wednesday, 15 February 2012, 7:00 AM