Hydration in infancy and childhood

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At birth, the total body water content is as high as 75%. It decreases during the first year of life in childhood to reach 60% at adult age.

Compared to adults, infants not only have a higher body water content, but also a higher surface area-to-body mass ratio, a higher rate of water turnover,1 a limited ability to excrete solutes, and a lower ability to express thirst. For these reasons, dehydration in infants is more quickly life threatening than for children or for adults.
However, because of the low potential renal solute load of human milk, healthy ad libitum breast-fed infants do not need additional water, even under conditions of high environmental temperature.2

Water requirements increase with age. Adequate Intakes for infants and children have been defined by the EFSA in 20102 and are summarized in the table below:

little girl drinking a glass of water
table : EFSA recommended adequate fluid intakes in children

EFSA recommended adequate fluid intakes in children2

As part of their nutritional education, children should be taught how to drink in a healthy way: attention should be paid to allow children good access to water throughout the day.

Encouraging children to favour non-caloric beverages such as water should be a component of broader advice on lifestyle and nutrition.

  • A study recently conducted in Germany has shown that a simple intervention with the sole focus of promoting water consumption effectively prevented overweight among children in elementary schools.3


  1. Fusch C, Hungerland E, Scharrer B, Moeller H. Water turnover of healthy children measured by deuterated water elimination. Eur J Pediat. 1993;152:110-4.
  2. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary reference values for water. EFSA Journal 2010; 8:1459-1507. doi:10.2903/j.efsa.2010.1459. Available online: www.efsa.europa.eu
  3. Muckelbauer R, Libuda L, Clausen K, Toschke AM, Reinehr T, Kersting M. Promotion and provision of drinking water in schools for overweight prevention: randomized, controlled cluster trial. Pediatrics. 2009;123:e661-7.

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