Water an essential nutrient

Maintaining an optimal hydration status is necessary for metabolism and water is therefore a key nutrient. Water entries are divided between endogenous water from oxidative metabolism and oral water intakes from beverages and water contained in food. The kidney ensures water homeostasis by concentrating and diluting urine under the influence of anti-diuretic hormone. Adequate intakes for water were defined by the Institute of Medicine and the European Food Safety Authority on the basis of observed water intakes in population subgroups, desirable water volumes per 1 000 kcal (>= 1.01/1 000 kcal) and desirable osmolality values in urine. A moderate dehydration can be accompanied by impaired cognitive and physical performances and chronic dehydration promotes many diseases, including kidney stones and urinary tract infections. Children and seniors are particularly at risk of dehydration. (C) 2015 Societe francaise de nutrition. Published by Elsevier Masson SAS. All rights reserved.