It is called blue gold, this is because without water, life could not exist. Even today, in the ancient winding road that leads to Sparta, in Greece, it happens to come across water springs, which gush water from the rocks of the mountain. And, around the source, there are taverns, small markets, there is life. Our body, once we reach adulthood, is composed of 50-55% water and water is essential to help regulate body temperature and the transport of nutrients to the cells, to support digestion and the work of the kidney, to prevent constipation and urinary tract infections, to stabilize heart rate and blood pressure. But how much water to drink every day? And what is the difference between normal water and fruit water that we hear a lot about in recent years? Let's try to understand.
How much water to drink
For a healthy person the fluid requirement is around 3 liters of water per day for men and 2.2 liters of water per day for women (Meinders et al, Ned Tijdschr Geneeskd, 2010). However, this quantity refers not only to the water drunk but also to the water taken through food and herbal teas. To get an idea of how much water to drink, Harvard University comes to the rescue and suggests, for healthy people, four to six glasses of water a day.
Drinking little water and risks for mood and the immune system
We saw, in the introduction, that staying hydrated allows the body to perform essential biological functions. However, drinking too little water can have other consequences as well, which we generally do not relate to water consumption. For example, it has been observed that those who drink little water, about 2 glasses a day, have a double risk of developing anxiety and depression compared to those who drink at least 5 glasses a day (Haghighatdoost et al, World J Psychiatry, 2018). Not only that, it was also observed that increasing the intake of water, about four more glasses, helped to decrease blood pressure and to increase body temperature. The latter effect is noteworthy as dehydration but also age tend to decrease the body temperature, with consequences on the metabolism and the immune system. Instead, an increase in body temperature, always within the limits of a healthy body, helps to increase metabolism and strengthens the body's defenses against external threats (Nakamura et al, Nutrients, 2020).
The benefits of flavored waters
In recent times there has been a lot of talk about fruit, herb and vegetable waters, stating that they are healthy drinks, more than water itself. Actually, these waters may have more properties than water but only if they are prepared as pure infusions, by heating the water. On the other hand, the flavored waters prepared by adding fruits, herbs, spices and chopped vegetables to a jug full of water and letting everything rest in the refrigerator for several hours improve the taste, with the benefit of taking in more water, but they no longer have advantages because active ingredients of fruit, vegetables and herbs pass to the water just in small quantities. In any case, the flavored waters prepared in this way have the advantage of making the water tastier and more pleasant to drink, in this way it is certainly easier to stay hydrated. It is completely different with regards to teas. In fact, the infusion of fruits in water at 100° C has been shown to extract important antioxidants, substances useful in the fight against aging and cellular degeneration. Peach and pomegranate showed the highest ability to release antioxidants, such as phenols and flavonoids. Apple, blueberries, strawberry and lemon also showed important ability to release in tea their flavonoids and anthocyanins, another important class of antioxidants. The maximum amount of antioxidants was detected with the infusion at 100° C and it gradually decreased until reaching the minimum quantity, around 20° C (Sahin et al, Antioxidants, 2013). Here is a further proof that cold prepared flavored waters cannot guarantee these same benefits. To get fruit teas you can find ready-made preparations in bags or you prepare all by yourself. For example, try bringing a liter of water to a boil. Remove from the heat and add two peaches cut into pieces, leave to infuse for fifteen minutes, then filter. You can flavor with cinnamon, lemon or even mint, add it all along with the peaches.