‘Ariston men hydor’ is Greek for ‘the best of all is water’. It was the first Olympic Ode of the Greek poet Pindarus dedicated to Hiero I of Syracuse, victor of the horse races in the Games of 476 BC. 25 centuries later (1968) the first article of the European Water Charter reads as follows: “There is no life without water. Water is a valuable resource that is essential for all human activity.”
Pure water is a clear, colorless, and odorless liquid that is made up of one oxygen (O) and two hydrogen (H) atoms. Its official chemical name is dihydrogen monoxide (H2O). The concept of water as a single chemical element endured in science until as late as the end of the 18th century. All life on earth is made up of a watery substance that is kept together by a more or less firm structure. It is a heritage from the past, from billions of years ago when life emerged from the oceans. Water has become such a ‘commodity’ that we hardly realize its importance. 97% of all water on earth is salt water in the oceans. Of the remaining 3% of fresh water, about two thirds is locked up in glaciers and icecaps. That leaves us with only 0,75% of fresh water readily available for consumptive use …
Water and our body
It is common knowledge that no life is possible without water and that we can only survive a few days without it. Of all the nutrients we need, water is without doubt the most crucial one. Up to 60% of the human body is water. A person that weighs 165 lbs contains 45 liters (11,9 gallon) of water. Newborns contain even more water: up tot 75% or 3,5 liters (0,925 gallon) for a baby of approximately 12 lbs. As we grow older, the amount of water in our bodies slightly decreases until about 50%, which still accounts for half of our total weight.
The functions of water in our body
Nearly all of the major systems in our body depend on water. It is a nutrient for body cells, a carrier of oxygen and nutrients, a solvent and a temperature regulator.
Nutrient for body cells
Our cells contain protein structures that are made up of water. The space between those cells is also filled with water. It is an important component of the fluids between body tissues; it helps to ‘cushion’ joints and is an effective lubricant around joints and muscles, including the peristaltic contractions of the stomach during digestion.
Carrier for nutrients and other materials
Water dissolves with other substances and carries the nutrients and other materials such as metabolites, waste products, hormones, minerals and vitamins around the body. Water also regulates body temperature by increasing or decreasing the amount of heat lost at the body surface.
Water has a very large specific heat capacity compared to other fluids. This means that a lot of heat is needed to heat water from one temperature level to another. It takes 10 times as much energy to increase 100 gram of water by 1 degree Celsius than the same amount of iron. Because our body contains so much water, external influences (hot or cold weather for instance) do not have a major impact on our body temperature.
Another important physical quality of water is its high heat evaporation. When the human body is heated as a result of physical activities or sports, the process of evaporation produces a cooling effect as a result of sweat production. Sweat, a fluid consisting primarily of water as well as various minerals such as sodium, evaporates through sweat glands in the skin. This process extracts heat from our body, cooling the blood and carrying that cooling effect back to the interior of the body.
Water as solvent
Water plays an important role in the body’s metabolic processes and is essential for cellular metabolism. Sodium and potassium are the main electrolytes involved in maintaining water balance within the body. They help maintaining a proper balance of water in and around the cells (also see paragraph on minerals). Water also improves digestion and acts as a solvent for food.