[Water--for life].

BACKGROUND

Water is an indispensable nutrient because of its physicochemical properties. People seem to consume more water than before although the scientific basis for this has not been firmly established.

MATERIAL AND METHODS

We present a short overview of data retrieved from the databases PubMed and Ovid, with particular emphasis on the regulation of water intake and water excretion in adults.

RESULTS

Water excretion is mainly regulated through the production of urine. Anti-diuretic hormone plays a key role. The intake of water is mainly governed via the poorly defined sense of thirst. Circumstantial evidence supports an increased intake of water to prevent certain cancers and cardiovascular diseases.

INTERPRETATION

Both excessive hydration and dehydration can cause serious illness, in particular in the elderly. There is a lack of firm scientific support for the beneficial health effects of increased water intake.