Water is essential in all cells of the human body. Without it, there is no life, and its lack in a few days can lead to death. Insufficient hydration of the body disturbs its balance and leads to many disorders of health. There is still much talk about the negative effects of coffee and tea on the body’s water management. Are coffee and tea dehydrating?
Proper hydration of the body
Water is the most important inorganic ingredient in the body. It performs many important functions, including supports metabolic processes, facilitates the movement of fecal mass, cleanses toxins, transports organic and inorganic components to all cells and regulates body temperature.
The demand for water depends on many factors, i.e. age, sex, weight or fat content. The body needs more fluids along with increased physical activity and increasing ambient temperature, which is caused by additional loss of water along with sweat. Because water is involved in metabolic processes, the demand for this ingredient increases with the increased energy value of the diet. Also, particular macronutrients are important because a large amount of protein in the daily diet contributes to increased diuresis.
The water level in the body should always be at the same level, i.e. the water balance must be zero. This means that the amount of water supplied with liquids and food and arising in the combustion processes should be equal to the amount of water excreted in urine, feces, and then exhaled air.
Dehydration of the body – symptoms
The body cannot store water. Therefore, its lack in the diet quickly leads to dehydration. The first symptoms are already present with a 1% water loss. There is then a decline in physical performance, reduced thermoregulation and a lack of appetite. With increasing dehydration, there are problems with concentration, headaches, drowsiness, nervousness, increased body temperature, and respiratory rate.
Dehydration of the body – effects
Dehydration leads to serious health effects such as
– pain and dizziness,
– cognitive impairment,
– motor function disorders,
– speech problems,
– Heart arrhythmia,
– pre-renal renal failure,
– changes in blood pressure,
– dry skin,
– malfunction of taken medicines,
– impaired salivation.
Coffee and tea as a source of water
The source of water for humans is drinking water, various types of beverages and food products. Coffee ranks second in the ranking of the most frequently consumed beverages.
The US Department of Agriculture (USDA) issued a statement recommending the intake of liquids without added sugar to reduce its amount in the diet. However, he does not pay attention to diuretic drinks, such as coffee and tea. The US Food and Drug Administration (FDA) recommends that healthy adults consume no more than 400 mg of caffeine per day, which is about 3-4 cups of coffee a day.
Do coffee and tea have a dehydrating effect
A popular myth about the allegedly draining effect of coffee and tea is based on the presence of caffeine in their composition. Caffeine is a natural substance that occurs in coffee, tea, and cocoa. This substance inhibits the reabsorption of sodium in the kidney tubules, and consumed in large doses (> 500 mg) has a diuretic effect.
The first study conducted by Fisher SM et al. On the diuretic properties of caffeine showed that regular consumption of this compound may contribute to the body’s specific tolerance to this substance. Besides, further research confirms that moderate consumption of caffeine does not contribute to significant dehydration of the body.
The purpose of one of the studies conducted by Grandjean A. et al. Was to determine the effect of various drinks, including caffeine, on the hydration status of the body. The study involved 18 men aged 24-39 who drank various caffeinated drinks, a total of 624 mg per day. The loss of water was determined by determining the amount of urine output. In men, there was a decrease in total body water by 2.7% and an increased urine output by 42%. Because the project participants consumed caffeine drinks every day, and 5 days before the study eliminated caffeine from the diet, the test results should be interpreted very carefully. Also, the authors themselves do not confirm the dehydrating effect of caffeinated beverages.
On the other hand, studies carried out by Killer SC, Blannin AK and Jeukendrup AE did not show the drainage properties of coffee. The study involved 50 men, who usually drank 5-6 cups of coffee a day. The experiment was divided into 2 trials, each of them lasting 3 days. During the study, men consumed 4 times a day 200 ml of coffee, which contained 4 mg of caffeine per kilogram of body weight or in the same amount of clean water. The physical activity of the participants and the solid and liquid food they eat were monitored throughout. The level of hydration of the body was tested before and after each trial. The study did not show statistically significant differences in the hydration of the body between coffee consumption and the consumption of clean water.
In the context of the dewatering effect of tea and coffee the most important is the dose, which was confirmed by the study of Seala AD et al. The researchers showed that the consumption of 6 mg of caffeine per kilogram of body weight per day can cause a diuretic effect, while 3 mg/kg bodyweight does not disturb the water balance in body.
In 2015, the European Food Safety Authority issued an opinion according to which the dose of caffeine above 6 mg/kg body weight per day does not contribute to the disturbance of the body’s water manage
The caffeine content in coffee and tea
Tea leaves contain 4.5% more caffeine compared to the amount of caffeine in coffee beans that contain a maximum of 2.5% of this compound. However, in the production of tea, the amount of caffeine decreases. The caffeine content in tea depends on the variety, growing conditions, degree of fermentation, type and brewing method. Namely, 100 g of black tea contains 2.8-3.8 mg of caffeine, whereas green tea only 1.0-2.1 mg of this substance.
The caffeine content in coffee also varies and depends on the type of coffee, the production process, and the brewing method. Robusta coffee contains twice as much caffeine as arabica coffee.
To sum up, to make tea and coffee dehydrating, drink on average 10 cups of black tea or 5 cups of brewed coffee per day.