Water is the most abundant component of the human body, and its regular consumption is essential for the proper functioning of the organism. Water requirements vary according to age, climatic conditions, time of year, diet, and level of physical activity.
Water in the body is lost throughout the day via the kidneys (through urine), through perspiration, and also via the lungs, skin, and faeces, although in smaller amounts. Water balance is achieved when these losses are offset by intake and the metabolic production of water. In men, water can constitute 60% of their body weight, and in women between 50% and 55%; however, this composition may vary depending on age and body composition, with the percentage increasing as fat mass decreases.
Water serves as a lubricant for joints and eyes, is involved in many of the reactions that occur in the human body, assists in the elimination of waste and the transport of nutrients, helps regulate body temperature, preserves skin elasticity, reduces the risk of kidney stone formation, and has a positive effect on weight control.
According to the European Food Safety Authority (EFSA), the recommended daily amount of water varies considerably, taking into account internal and environmental factors as well as the individual's stage of life. This can range from 0.8–1.0 litres per day in children aged 7–11 months and increase to 2.7 litres per day in infants, with the recommended values for healthy women and men being 2 litres per day and 2.5 litres per day, respectively [1].
Dehydration occurs when the loss of body fluids exceeds intake, resulting in a water imbalance that can affect various physiological functions and lead to symptoms such as thirst, dark and strong-smelling urine, fatigue, dizziness, headache, cramps, and sunken eyes [2]. If left untreated, and depending on its severity, this condition can lead to complications such as hypotension, constipation, urinary tract infections, kidney stones, renal failure, hyperthermia, and convulsions [3].
Strategies to promote good hydration:
- Always have a water bottle nearby.
- Drink small amounts of water frequently throughout the day.
- Increase liquid intake if you notice your urine is more concentrated, if you sweat due to physical exercise or on hot days, and in cases of fever, vomiting, or diarrhoea.
- Avoid alcoholic beverages and the excessive consumption of drinks high in caffeine.
- Consume foods or dishes rich in water, such as soup, stews, broths, and salads.
- Choose beverages such as milk or liquid yoghurts, teas, or herbal infusions (excluding diuretics such as horsetail, green tea, hibiscus, dandelion, or fennel), water flavoured with pieces of fruit, natural juices, nectars, etc.
- Eat water-rich fruits and vegetables such as cucumber, tomato, courgette, watermelon, pumpkin, melon, and plum [4].
Produced by the Dietetics and Nutrition trainee students of the University of Algarve, Carolina Faria (no. 76569) and Eduardo Pedro (no. 72355), under the guidance of nutritionists Victoria Ursu (5947N) and Marina Augusto Estevão (0365N).
22, March 2025
