L'eau comme nutriment essentiel, base physiologique de l'hydratation
Source : European Journal Of Clinical Nutrition
Dans cette étude franco-suisse, les chercheurs mettent en évidence les rôles complexes et nombreux de l'eau dans notre corps. A la fois, bâtisseuse, "éboueuse" de nos déchets, mais aussi conductrice de nutriments d'une cellule à une autre, elle sert à réguler la température de notre corps ou à absorber les coups. La déshydratation peut être dramatique notamment chez les jeunes enfants ou chez les personnes âgées et atteindre la conscience, avec des incohérences verbales, tachycardie, et hypotonie des globes occulaires. La prise d'eau recommandée est toujours de 1,5 l par jour, dans des conditions normales.
European Journal of Clinical Nutrition (2010) 64, 115–123; doi:10.1038/ejcn.2009.111; published online 2 September 2009
Water as an essential nutrient: the physiological basis of hydration
E Jéquier1 and F Constant2
1. 1Department of Physiology, University of Lausanne, Pully, Switzerland
2. 2Nestlé Waters, Paris, France
Correspondence: Honorary Professor E Jéquier, Department of Physiology, University of Lausanne, Av. de Rochettaz 10, Pully 1009, Switzerland. E-mail:
How much water we really need depends on water functions and the mechanisms of daily water balance regulation. The aim of this review is to describe the physiology of water balance and consequently to highlight the new recommendations with regard to water requirements. Water has numerous roles in the human body. It acts as a building material; as a solvent, reaction medium and reactant; as a carrier for nutrients and waste products; in thermoregulation; and as a lubricant and shock absorber. The regulation of water balance is very precise, as a loss of 1% of body water is usually compensated within 24 h. Both water intake and water losses are controlled to reach water balance. Minute changes in plasma osmolarity are the main factors that trigger these homeostatic mechanisms. Healthy adults regulate water balance with precision, but young infants and elderly people are at greater risk of dehydration.
Dehydration can affect consciousness and can induce speech incoherence, extremity weakness, hypotonia of ocular globes, orthostatic hypotension and tachycardia.
Human water requirements are not based on a minimal intake because it might lead to a water deficit due to numerous factors that modify water needs (climate, physical activity, diet and so on). Water needs are based on experimentally derived intake levels that are expected to meet the nutritional adequacy of a healthy population. The regulation of water balance is essential for the maintenance of health and life. On an average, a sedentary adult should drink 1.5 l of water per day, as water is the only liquid nutrient that is really essential for body hydration.