Questions and common beliefs about water.

Apr 26, 2011

Water is not an essential component of the human body

False. Water plays an important role in the functioning of the human body, as it is one of its major components! Indeed, the human body is mainly composed with water, whose percentage decreases when the body ages, from 75% for infants to 60% for adults and 50% for elder persons.

These proportions vary in the different organs as well. While water represents 73% of an adult’s brain, it constitutes 83% of his lungs, 79% of his kidneys and of his muscles. That is to say, if you don't drink enough water throughout the day, you will feel the effects of this lack.


Reference: Mitchell HH et coll. The chemical composition of the adult human body and its bearing on the biochemistry of growth. The Journal of Biological Chemistry, 1945: 625-637

You don't necessarily need to drink water, because you lose little amount of it every day.

False. Every day, in temperate climates, a healthy sedentary adult loses on average 2.5 liters of water per day. You lose water through urine (around 1.6l/day), through skin (perspiration) (around 450ml/day), through water steam eliminated when breathing (around 300ml/day) and through the stools (around 200ml/day). That's why, everyday, you need to compensate these water losses with drinks and food.

Reference: Jéquier E, Constant F. Water as an essential nutrient: the physiological basis of hydration. European Journal of Clinical Nutrition (2010) 64, 115-123.

The water you need to stay well hydrated is only contained in drinks

False, the water you need to maintain your water balance comes mainly from beverages but food brings water that contributes to the overall daily water intake.

Some foods are richer than others, like fruits and vegetables which can contain 90% to 95% of water. It is estimated that, in average, the water contained in the food contributes to about 675ml of total daily water intake.

Moreover, our organism produced every day between 250 to 350 ml of water. Thus, to compensate for the daily water losses of 2.5 liters, a healthy sedentary adult living in temperate climate should drink 1.5 liters of water per day. Thus, the food you eat and an adequate intake of water (8 glasses of water per day – 1 glass = 200 ml for adults), will help you to maintain your water balance.


When you are thirsty, drinking one or two sips of water is enough

No, it's not enough. Actually, drinking one or two sips just helps to ease your thirst without necessarily restoring your water balance. In fact, the thirsty feeling tells you your body is dehydrated, more or less depending on your thirst intensity. To maintain the water balance, you need to drink water regularly throughout the day, before the sensation of thirst appears.

Drinking while eating impedes digestion

False. Drinking 1 to 2 glasses of water during a meal does not prevent the digestion process to start in the stomach. This process is above all related to the secretion of digestive enzymes. So remember to drink water regularly throughout the day, including mealtimes.

Drinking a lot is not recommended, as it can weaken the kidneys.

False. To the contrary, the kidneys require water to remove waste from the body. Therefore, the kidneys function more efficiently in the presence of an abundant supply of water. Furthermore, the greater the volume of urine, the better their dilution. It decreases the risk of urinary gravels.

A natural mineral water is always highly mineralized

False. Natural Mineral water can have a low or high mineral content. So just look at the dry residue amount on the label. It represents the weight of the ashes (minerals and trace elements) obtained after the total evaporation of water because of the heat. If this residue is below 500mg/l, the water is low in minerals. On the other hand, a dry residue equal to or higher than 1,500mg/l means the water is highly mineralized. Thus, we have the opportunity to choose the water according to its taste but also to our specific needs.

Drinking a calcium-rich mineral water everyday could create gravels

False, because the human body absorbs only the amount of calcium needed and eliminated the excess via urine.

It is important to avoid drinking always the same water.

False. If you have found water that meets your expectations, why would you change? If, for example, you choose to drink a calcium-rich mineral water because you do not eat enough dairy products, changing water is not appropriate.

Natural Mineral water does not have more qualities than tap water.

False. Natural Mineral waters come from groundwaters, and, as a consequence, they are protected from surface pollution, whereas tap water comes from water surface and needs a treatment in order to be drinkable. Natural Mineral water is bottled as it is, as soon as it gets out of the source, and it is almost stable in its characteristics once in a bottle. This is guaranteed to the consumer through daily bacteriological controls.