Drinking water is the most important foodstuff. However, water is not only needed to quench thirst and prepare food. A large amount of water is also used for hygiene and in the production of many goods.
In the USA, average per capita water consumption is currently around 200 liters per day; in Central Europe, the figure is around 120 liters. At the same time, there is an extreme water shortage in many regions of the world. For example, 748 million people worldwide have no access to good drinking water. World Water Day is intended to help gradually eliminate these shortcomings and raise awareness of water as a valuable resource.
Water is the source of life
In the beginning, they were single-celled organisms: Bacteria, simple algae, etc. Their only possible habitat remained the water for many millions of years. It was only when individual cells joined together to form groups and grew into larger creatures that it became possible to expand the habitat. In the course of evolution, these creatures developed special cell assemblies that could effectively protect the organism from water loss even on land: solid and, above all, largely water-impermeable scales, shells, skins, barks, etc.
Even if leathery skin, woolly fur or firm scales initially give a different impression: In dinosaurs, birds, cats or humans, the internal organs can only function if there is an abundance of water. All so-called higher organisms – including humans – consist to a considerable extent of water. In a newborn baby, it is about 70 percent. Admittedly, the value drops to less than 50 percent with age. But in every phase of life, the organism is dependent on a supply of water.
Water is lost constantly
Although our skin provides effective protection for the large amount of water in our body, there is of course still a permanent loss of fluid. The sweat pores secrete fluid to regulate temperature. And fluid is also lost through breathing, defecation and urine. The latter in particular is also necessary, because water serves here as a solvent for all kinds of metabolic products. If these were to accumulate in the body, poisoning would result.
In the human organism, even a loss of a few liters causes a dangerous disturbance of the balance. For this reason, we can only live for a short time without increasing our fluid intake. If all sources of water were to dry up from one day to the next, death from thirst would occur after only three to four days – depending on the ambient temperature. In fact, we humans already feel thirsty after a water loss of about 0.5 to 3 percent. Extrapolated to an adult with a body weight of 80 kg, this corresponds to 0.2 liters – about as much as fits into a normal water glass.
Drink before the thirst
Every day, humans need about two to three liters, depending on their body weight. We take in part of this through our food. We have to drink the rest – at least one to one-and-a-half liters, and more during sporting activities and physical work. The best thing to do here is not to wait until we feel thirsty, which ultimately alerts us to a deficiency. Drinking too little not only puts a strain on the kidneys. Stool and blood also become more viscous. While the former leads to unpleasant constipation, the latter can weaken the circulation.
Fortunately, water shortage is not an issue in our latitudes. Even if there is no precipitation for several weeks and large parts of the vegetation suffer, there is still plenty of groundwater and usually also surface water available, which is treated to produce high-quality drinking water. And this water is among the best controlled foodstuffs in the world. Samples are taken and analyzed on an ongoing basis. The Federal Environment Agency points out that the quality of tap water in Germany is generally so good that it can be used to meet one’s liquid needs without hesitation.