Drinking two liters of water a day is excessive, says study

For years the idea has been perpetuated that it is necessary to drink two liters of water a day.

However, a new study from the University of Aberdeen in the UK, published on Friday (25), shows that the recommended water intake of eight glasses (about two liters) per day rarely corresponds to our real needs and, many times, can be too high.

According to the research, the amount needed to be drunk varies between 1.3 to 1.8 liters per day, depending on age, climate and where the person lives.

According to the publication, previous research in this area was based on small groups of people and tended not to consider water ingested through food.

The new study applied a more objective approach to 5,604 men and women, aged between 8 days and 96 years, from 23 different countries.

The technique involves people drinking a glass of water in which some of the hydrogen molecules have been replaced with a stable isotope of hydrogen called deuterium.

The work showed that water turnover is higher in hot and humid environments and at high altitudes, as well as among athletes, pregnant and lactating women and individuals with a high level of physical activity.

The biggest factor, however, was energy expenditure. The highest values ​​were observed in males between 20 and 35 years old. The water turnover of this group averaged 4.2 liters per day. It subsequently declined with increasing age, averaging just 2.5 liters per day in men in their 90s.

Among women, the average water volume between ages 20 and 40 was 3.3 liters a day, and it also dropped to about 2.5 liters by age 90.

Water turnover was also higher in developing countries. This is likely because, in developed countries, air conditioning and heating protect individuals from exposure to extreme environmental conditions that increase demand for water.

Professor John Speakman, from the School of Biological Sciences at the University of Aberdeen, explains that water renewal is not equal to the need for fresh water.

“A man in his 20s has an average water volume of 4.2 liters per day, he does not need to drink 4.2 liters of water per day. About 15% of this value reflects surface water exchange and water produced from metabolism. Since most foods also contain water, a substantial amount of water is provided by food alone.”

The research resulted in a general equation for predicting water volume that can be used to anticipate the effects of future changes, for example, in climate and population demography. This will help countries anticipate their future water needs.

The Doctor. Yosuke Yamada, section chief at the National Institute of Biomedical Innovation, Health and Nutrition in Japan, who co-authored the paper, said: “The equations we generate to predict water turnover will be of great benefit in modeling global water needs.” .

Former Aberdeen PhD student Xueying Zhang, co-first author of the paper, added: “Calculating how much water humans need is becoming increasingly important due to explosive population growth and increasing climate change. Water turnover is related to many health parameters, including physical activity and body fat percentage, making it a potential new biomarker for metabolic health.”

(Posted by Marina Toledo)