How much water do you really need to drink? Will my skin start to look more hydrated if I drink more water? And is it true that coffee dehydrates the body?
Here's what science has to say about it.
The trend became apparent when, in the 1970s, in the United States, brands such as Evian and Perrier began to market bottled water as a symbol of high status. Now people drank water not only during meals, but all day long. A bottle of water has become a symbol of good health.
Nothing indicates that the situation has changed over time.
In the American edition of The Atlantic, you can read that reusable water bottles of certain brands have become a typical accessory for the famous generation of "millennials". Some will cost $ 49, while others cost up to $ 100, although there are still crystals in this water that are said to promote "peace and inner harmony."
The British The Telegraph wonders if reusable water bottles have become "an analogue of the so-called it-bag", that is, popular and often very expensive branded bags, on which sellers have made a lot of money.
Water is a good drink for someone who is thirsty. But how much do we really need to drink? The short answer is until we quench our thirst. Jenny Nyström, professor of renal physiology at the Salgren Medical Academy in Gothenburg, talks about this.
“Basically, the fluid balance in our body is regulated by the kidneys. They are the ones who make sure that there is enough water, salts and other substances in it, and they also save us from waste and everything unnecessary,”says Jenny Nyström.
All this happens automatically, and we don't need to do anything. In addition, the kidneys are a very powerful organ. If we are generally healthy, then we can, for example, donate one of the kidneys to someone and still live normally.
Dagens Nyheter: So you shouldn't be afraid of dehydration if you eat and drink normally?
Jenny Nyström: No, not worth it. Thirst is one of the strongest feelings. It signals that a person needs to drink. This can also be understood if, for example, you have a very small volume of urine and it is dark in color. But in conditions of normal temperature and normal access to water and food, there is no need to think about this especially much, because everything happens by itself.
It is important to remember that fluid enters our body with food.
If you train intensely or, for example, run a marathon, you need to compensate for the loss of fluid more actively than usual. It is also important to replenish the salts that the body loses through sweat. If in such cases you drink only plain water, the salt balance may be disturbed, and this is dangerous.
“It's very important to remember to eat something salty if you sweat a lot,” says Jenny Nyström.
And what about coffee and tea, is it true that they are diuretics? This is a common belief that has no scientific evidence, she says.
“Scientists see that if a person drinks a lot of coffee, there may be a slight diuretic effect. But in such cases, we are talking about much more caffeine than what ordinary coffee drinkers get,”says Jenny Nyström.
Professor Olle Melander, chief physician and visceral specialist at Lund University, suggests that the myth of coffee as a diuretic may have a natural explanation.
“After all, a lot of liquid gets into the body when we drink coffee. If we only drank espresso in small cups, this myth probably would not have formed,”he says.
But alcohol is a diuretic, says Jenny Nyström. The fact is that alcohol blocks the production of the hormone vasopressin, a substance that is usually released when we need to "save" water in the body. Therefore, after drinking alcohol, we get rid of more fluid than usual.
Do we become more beautiful from the water? One of the most common advice from cosmetologists is to drink plenty of water, as it is believed that this improves the skin. But there is no scientific evidence that if you drink water in buckets, your skin will begin to glow. Of course, no one has done major studies on this topic, but none of the individual experiments conducted indicate that water is a miracle cure for the skin, says Jenny Nyström.
“There is no skin cleansing that way either. If we drink large amounts of water, it will pass out of the body rather quickly, and there is no sign that more water than usual will get into the skin to carry away waste products from there. No such mechanisms are known about."
However, dehydration affects the skin. But, according to Ulle Melander, drinking a lot of water for the sake of improving the skin in this case is pointless, simply because few people suffer from dehydration to such an extent. If a person is truly dehydrated, this is already a life-threatening condition.
According to Jenny Nyström, the best drinking advice is the classic recommendation to listen to your body. Feeling thirsty? Drink a glass of water.
"If the body is functioning as it should, in this matter you can focus on your own feelings."
You may have also heard that it is good to drink plenty of water after a massage, as it helps the body to flush out "waste materials."
In favor of this theory, Jenny Nyström also cannot say anything. But it can really be nice to replenish your body fluids by spending an hour in a warm massage room so you don't get dizzy when you get back on your feet.
The body gets rid of water on a daily basis - partly through urination, but also through breathing, feces and sweat. The main guarantee of well-being is to drink as much water every day as is excreted and to produce at least 1.5 liters of urine. How much to drink depends on each specific organism. This can be influenced by illness, ambient temperature and physical activity when a person sweats more than usual.
“But the absolute minimum for survival is one liter per day,” says Olle Melander of Lund University.
He and his fellow scientists have been observing for many years how water reduces the risks of various diseases such as cardiovascular diseases and type 2 diabetes. Observations began when it was noticed that people who are at high risk and can potentially develop type 2 diabetes, over time, high levels of the hormone vasopressin are found in the blood, which causes the kidneys to retain water in the body if a person drinks too little.
Scientists have conducted various studies to find out how water can help this group of people. One of them was that several people who drank little and had high levels of vasopressin in their bodies had to drink an additional 1.5 liters of water per day for six weeks.
“After that, their blood sugar levels dropped significantly,” says Olle Melander.
Scientists are now trying to find answers by conducting a much larger study involving more subjects and control groups. It will come to an end in a few years. Already, however, there are results from other experiments, and they indicate that a certain amount of water per day reduces the risk of, for example, urological infections and kidney stones.
Scientists hope that a large new study will help determine as accurately as possible the optimal amount of water needed to reduce the risk of disease. But how much you need to drink to feel good depends on the individual characteristics of the organism, Melander believes.
“This partly depends on what exactly a person eats and in what quantities, as well as on how much he moves and in what temperature environment. Therefore, it is difficult to give unambiguous recommendations”.
When there is too much water
Extremely rare cases are known when a person drank so much water that he died. This is primarily due to the fact that drinking a very large amount of water in a short time can disrupt the balance of important salts in the blood. This condition is called hyponatremia.
Water and our body
A very large percentage of our body is water - like all other life forms on Earth. Usually the cage is at least 70% water. An adult man is about 60% water, and a woman is about 55%.
Water enters the body with fluids and food. The body signals the fact that the water balance begins to be disturbed with the help of a feeling of thirst.