Water is the main component of the body: it represents around 60% of the weight of an adult's body. A little more in infants (~75%), and a little less in elder persons (50%) (1). 

 

Water, presents in each cell and organs of the human body, plays several key roles. It acts first as a building material. Water is also a solvent, a reaction medium, a reactant and a reaction product. It helps to keep the body at the right temperature, through its evaporation at the surface of the skin. Moreover, water in the body transports nutrients to cells – it is the major component of blood (blood is 92% of water). Therefore, it maintains vascular volume and allows blood circulation which is essential for the good functioning of the different organs of the body. Water also helps removes waste products from the body. (1)

In other words, not drinking enough water may, sooner or later, leads to dehydration. That is how important water is! 

 

 

What does "not drinking enough water" mean?

 

An individual's water needs depend on his age, his gender, the climate, his physical activity… (1-2).  However, there is a recommendation: it is estimated that a healthy sedentary adult, living in temperate climate, should drink in average 1.5 liters of water per day (1).

 

 

What happens if you don't?

 

An insufficient water intake disturbs the water balance. Indeed, to maintain the water balance, the water inputs must be equal to the equal outputs. Water intakes are composed of: the water you drink (~ 1.5 liter per day*), the water you eat (on average 675 ml per day) and the water your body produce (around 300ml per day). Water outputs include: the water you lose via urine (around 1.6 liters per day), the water lost through the skin (approximately 450ml per day) and the lungs (~300ml/d), and finally the water in the feces (~200ml/d). (1)

 

When you maintain the water balance, you stay well hydrated. On the other hand, if the water intakes are lower than the water losses, you can experience a hydration deficit and thus one step further becoming dehydrated. 

 

*For a healthy sedentary adult living in temperate climate

 

 

What are the consequences of the dehydration?

 

Let's talk especially about people who do not drink enough every day: For instance, they drink 1 liter per day instead of the 1.5 liter recommended for a healthy sedentary adult living in temperate climate. Let's have a look at the consequences on short, medium and long term… 

 

> Thirst and dry mouth feeling. Indeed, any decrease in blood volume caused by an insufficient hydration leads to the activation of receptors located in the wall of the vessels, as well as the emission of a signal that is going to stimulate the thirst center in the brain (3). Concerning elderly persons, the thirst feeling is often altered because of the aging process (4). 

 

> Other signs of mild-to-moderate dehydration. These persons often feel tiredness, headaches, dizziness and muscle weakness… (1)

 

> Higher risk of urinary tract infection. Indeed, not drinking enough leads the hypophysis to exude an anti diuretic hormone (ADH), which increases the re-absorption of water at the kidney level, and can cause the reduction of the urinary volume and to more concentrated urine (3,5). This allows microbe outbreaks and increases the risk of urinary tract infections. As you may know, drinking enough every day reduces the risk of urinary tract infections (5).

 

Some talk about drier and wrinkled skin; others affirm it increases the cardiovascular risk, but that has not yet been proven.

 

Tips for drinking enough water, every day

 

> Start the day with a big glass of water.

> Drink during and between meals.

> If possible, always have a bottle of water at your fingertips. When you see it, you will remember to drink!

> Do not wait for a feeling of dry mouth or thirst to drink water. 

> Set an objective: drink 8 glasses of water* per day!

 

 

As discussed above, not drinking enough water may lead to insufficient hydration or one step further to dehydration. So let's enthusiastically drink your 8 glasses of water* every day, and appreciate them, with the feeling to indulge yourself!

 

*For a healthy sedentary adult living in temperate climate; 1 glass = 200 ml

 

 

References:

 

1- Jéquier E, Constant F. Water as an essential nutrient: the physiological basis of hydration. Eur J Clin Nutr 2010, 64: 115-23.

2- Dietary Reference Intakes – The essential guide to nutrients requirements. Institute of Medicine of the National Academies, Washington, DC, 2006, p.543

3- Ganong WF et al. Review of medical physiology. 22nd edition Lange science 2005

4- Philips PA et al. Reduced thirst after water deprivation in healthy elderly men. New Engl J Med 1984; 311: 753-9. 

5- Popkin M et al. Water, hydration and health. Nutr Rev 2010, 68 (8): 439-58

 

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.

 

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

 

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. 

Children may not drink enough water at school.

 

It can be explained by several reasons: they usually only have access to water in the toilets (that's why girls refrain themselves from going to the toilets and drinking), teachers forbidding them to leave the class to go urinate, they are not allowed to drink during the class course… All geared may expose kids to insufficient hydration. 

 

In France, children start their school day with a hydration deficit, like in the US.

 

A recent French study shows for the first time that almost two thirds of children (62.2%) are not properly hydrated when they go to school in the morning, despite a breakfast. This survey was carried out on a sample of 529 French school children aged between 9 and 11, and the following criteria were studied: 

    • The urine concentration in the morning after breakfast

    • The nutrient intake of the breakfast eaten (food and drink) 

Also, this study outlined that this hydration deficit concerned boys (72.5%) more than girls (51.6%). It can be concluded that the amount of fluids consumed at breakfast is not sufficient to ensure good hydration throughout the morning, hence the need for an additional fluid intake before lunchtime. These results are similar to that found in the US where 64 % of children are insufficiently hydrated in the morning before going to school.

 

> Why it is important for children to stay well hydrated?

 

Whatever their age and weight, it is important for children to get enough fluids on a daily basis because all of the body’s organs (heart, lungs, brain, kidneys, etc.) need to be sufficiently hydrated in order to function properly.

In fact, when children drink water, it hydrates their little body. Water flows through a remarkable irrigation system that distributes water down to the tip of their toes but also up to their brain. The brain, which is a complex organ, allows us to think, memorize, and learn and much more! Even today, nobody knows how it fully works. But, one thing is sure: more than 2/3 of the brain is made of water*. It is during childhood, which is an important period of learning that the brain mainly develops. As a consequence, a good hydration is important for the children’s whole body and also for their brain to function properly. 

So, what can we do to help kids to drink  water and to like it…?

 

*73% of an adult’s brain consists of water 

 

> How can we help kids to drink water…?

 

-  Give them the reflex of drinking water at the early stage 

 

Teach them how to drink, especially water. Good habits are best learned at an early age. When they are thirsty, then, offer them water without sugar or syrup. Just plain water! 

 

Ensure there is always a visible bottle of water in the kitchen, on the table, in the fridge… so that it becomes the first choice, easy to drink for everyone and, among others, for your children (or teens). 

 

- Make them take water at school…

 

- Slip a small bottle of water in their school bag

 

- Being autonomous, the kid has the opportunity to drink throughout the day 

 

- Don't forget to make them drink a big glass of water every morning, before leaving for school.

 

- When they are back from school, give them a big glass of water with their snack.

 

 

- Top tips to make them want to drink water 

 

- If they do not really like still water, offer them alternately sparkling: bubbles are magical to them!

 

- To enjoy different tastes, you can also slip a small of lemon (take off the skin), to slightly flavor the water.

 

One final advice… Set the example: If everybody drinks water in the family, children will be glad to do the same. They won't even question it! Don't forget to make water the first choice when it comes to daily hydration!

By Dr. Laurence Plumey

 

Cold weather, wind and home heating dry out the skin and leave it rough and flaky.

In other words, it is essential to protect and to moisturise it. Let's go back to basics, to understand better the nature of the skin and to understand its needs, in order to know how to take care of it and which products to apply. 

 

 

 

The skin is a multilayer organ!

 

Around 3 mm thick, the skin contains 70% water (1). It protects us and allows us to be closely linked to our environment, thanks to the tactile sensations we can feel. It reaches a surface of 2 m2 and a weight of 4.5 kilos for adults  Millions of glands, hair follicles, blood capillaries and nerve fibres  run into the skin. Well, skin is a high-tech organ we must take good care of!

 

 

Skin is composed of 3 juxtaposed layers: epidermis (external), dermis (middle) and hypodermis (deep). Epidermis, the most exposed layer, protects us from external damages. 

 

 

- Epidermis: above all a protection

It is rich in keratinocyte cells, which migrate towards the surface of epidermis and mutate into flat cells without nuclei, rich in keratin and insoluble in water. These cells are called corneocytes, held on each other, especially thanks to a sort of cement rich in keratin, lipids and oily acids and ceramids (2).  This hydrolipidic film protects the skin and gives it flexibility. These corneocytes die and renew very fast; it is the natural desquamation phenomenon. In the epidermis, there are also melanocytes, responsible for the colour of the skin, Langerhans cells, that attack pathogenic bacteria, Merkel's cells, in contact with nerve termination, that participate to the touch function. This film is reinforced by sebum, a lubricant secreted by sebaceous glands, protecting the skin against drying (1,2).

 

 

 

Dermis: a function of support and nutrition of epidermis

 

Containing 80% water,  the dermis is very rich in elastin and collagen fibres, embedded in glycoprotein gel. It is highly vascularised and 10 to 40 times thicker than the epidermis. It allows the skin to resist tensions and tractions and it gives it elasticity. It helps healing and thermoregulation. (3). 

 

 

Hypodermis: can host fat cells

 

It is the deepest and the thickest layer of the skin. It can be more or less rich in fat cells, depending on the context and the location (abdominal, femoral). It also hosts the bulbs of the sweat glands: we have 2 to 5 million in our body. They produced sweat: 400 ml per day minimum and up to 1 litre per hour! (4,5)

 

 

 

How to protect your skin during winter

 

During winter, you skin hurts: cold weather tightens the pores and reduce sebum production, therefore decreasing the quality of the hydrolipidic film. Cold weather is often dry, as is the air in heated houses. That's why it decreases moisturising capacities by exterior environment. That is why the skin becomes dry, tensed and it can develop pruritus. 

 

 

 

Here are 8 recommendations to preserve your skin, on the face and on the body:

 

 

1 - Every morning and every night, cleanse your skin to remove impurities and apply an emollient, moisturizing and lipid-rich cream.

 

2 - Avoid taking very hot showers, as they are an additional irritant for your skin.

 

3 - During showers, use hydrating soap with oils, shea butter, glycerine, etc.

 

4 - After a shower or bath, dab your skin with a towel rather than rubbing it, and apply your moisturising lotion or cream.

 

5 - Scrub regularly (once every 15 day in average) to remove dead cells from face and body. Then, use a emollient cream, because its lipids will enter the skin much better once it is free from dead cells. 

 

6 - Place humidifiers in he rooms of your house, in order to maintain a certain humidity quota. Aerate your house everyday.

 

7 - Protect your lips as well, with a moisturising balm.

 

8 - And do not forget your hands: avoid contact with dishwashing detergent, especially under very hot water, Apply a highly moisturizing cream on your hands everyday. 

 

To conclude, skin is too precious to let it be damaged during winter: let's protect it with high quality emollient creams. 

 

 

 

Sources:

 

1. Gougerot-Schwartz A. Hydratation et produits hydratants. EMC , 2000, 50 – 160 -  B.10

2. Structure de la peau. Cours de Formation “Comprendre la peau. Histologie et histophysiologies de la peau et de ses annexes. Ann.Dermatol.Venereol, 2005, 1342, 8S5.48

3. Barry M.Popkin and coll. Water, hydration and health. Nutrition Reviews, 2010, Vol 68 (8) : 439-458

4. Jequier E, Constant F. POurquoi faut-il boire de l’eau ? Pour maintenir la balance hydrique. Cah Nutr Diet, 2009, 44, 190-7.

5. Sawka MM and coll. Human water needs. Nutr Rev, 2005 : 63, 530-9

Daily calcium needs must be covered to constitute and maintain bone capital. 

 

To do so, a daily intake of 3 dairy products is usually recommended, but sometimes this is not achieved. In this case, a regular intake of calcium-rich mineral water is a good  complement that could, if the calcium content of the water is high enough, help to meet the daily calcium needs estimated to be 800mg in Europe.

 

But the question is: Is this calcium absorbed as well as the calcium in dairy products? And the answer is: Absolutely!

 

The absorption of the calcium contained in calcium-rich mineral waters is as good as the absorption of calcium in dairy products.

 

Several studies demonstrated that the calcium contained in water is absorbed as well as the calcium in dairy products (milk and cheese) and even in medicines: the absorption coefficient of calcium in dairy products is around 25% to 35% (1), when that of the calcium in mineral waters is from 23% to 47.5% (2).

 

As calcium intake decreases, the efficiency of calcium absorption increases (and vice versa) (3). However, the amount of calcium really absorbed will be increasing with the highest calcium intake. Thus, for example, after consuming 100mg of calcium, the absorption rate reaches 47.5%  (i.e. 47.5mg of calcium is absorbed), when for 500mg of calcium taken, 23.8% is absorbed (i. e. 119mg of calcium is absorbed) (2). 

 

Note that calcium absorption doesn’t depend only on the size of dose; it’s also influenced by the form of calcium and the presence or absence of some food components such as oxalic acid or phytic acid (3). However, in mineral waters, calcium absorption is similar in healthy people whatever the type of salt is: calcium sulphate or calcium bicarbonate (2).

 

 

Beneficial effects on  bone mineralization

 

A number of studies showed that drinking a calcium-rich mineral water leads to a decrease of the bone resorption indicators (4-6). 

 

 

One litre of calcium-rich mineral water can contribute to meet 50% of the daily calcium needs of an adult!

 

The average recommended calcium intakes for adults are 900mg/d in France and 1000mg/d in USA. For adolescents, these needs are increased by 300mg/d in both countries making them at 1200mg/d in France and 1300mg/d in USA. Seniors and elderly persons have also increased calcium needs: 1200mg/d (1,3).

 

 

The daily consumption of one litre of calcium-rich mineral water, containing 500mg of calcium per liter covers:

- 50% of the Dietary Reference Intakes (DRIs) for calcium in USA for adults

- 60% of the DRIs for calcium in France for adults 

- 42% of the DRIs for calcium in France for adolescents 

- 38% of the DRIs for calcium in USA for adolescents 

- 42% of the DRIs for calcium of an elder person. 

 

Drinking a calcium-rich mineral water is therefore a good way to contribute meeting the daily calcium needs as part of a balanced diet.

 

Choose water carefully, depending on your  preference and specific needs.

 

 

References:

1) Apports Nutritionnels Conseillés pour la Population Française. « Calcium » L. Guéguen. p.131-140 - Ed Tec et Doc Lavoisier 2001.

2) Constant F et al. Les eaux embouteillées. Cah. Nutr.Diet, 2011, 46, 40-50

3) Dietary Reference Intakes. The essential guide to nutrient requirements. Washington DC: Institute of medicine of the national academies; 2006. p. 1—543.

4) Roux S et al. Biological effects of drinking-water mineral composition on calcium balance and bone remodeling markers. J Nutr Health Aging 2003 ; 7 (6) : 1-5

5) Meunier PJ et al. Consumption of a high calcium mineral water lowers biochemical indices of bone remodelling in postmenopausal women with low calcium intake. Osteoporos Int 2005 ; 16 : 1203-9

6) Wynn E et al. Alkaline mineral water lowers bone resorption even in calcium sufficiency : alkaline mineral water and bone metabolism. Bone 2009 ; 44 : 120-4