Today's news services ran an interesting story regarding the recommended dietary intakes for water of 9 - 13 cups as highlighted in the Institute of Medicine's Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2004) . CBS , NBC , ABC , the BBC, the Guardian , the Telegraph and Daily Mail , among others have all featured articles saying that there is not a single drop of evidence behind the myth of drinking eight glasses or more of water a day.
It turns out that the dietary recommendations from noted medical authorities as well as self-appointed health gurus to drink two or more liters of water per day are totally unsupported by any scientific evidence. Doctors Dan Negoianu and Stanley Goldfarb from the University of Pennsylvania in Philadelphia reviewed all the published clinical studies on the subject and concluded that no data exists for average healthy individuals regarding the amount of water they should consume on a daily basis.
Indeed, it is unclear where this recommendation came from," the University spokesman added.
Their research also debunked the myth that drinking water makes the skin more supple and made it easier to lose weight. "There is simply a lack of evidence in general," they reported in the Journal of the American Society of Nephrology .
Reuters reports that this was not the first time such a conclusion was made since Dr. Heinz Valtin of Dartmouth Medical School found the recommendations to drink that amount of water to be totally lacking in scientific merit.
Because we all have specific individual needs for water, Goldfarb recommended, "If you're thirsty, drink. If you're not thirsty, you needn't drink."
This most recent article highlights the specificity of an individual's metabolic need, a situation paralleled by salt intake. The human body has an ability to excrete 250 times the maximum recommended intake of salt - an amount of salt that is virtually impossible for anyone to consume. In other words, our salt consumption is not limited by our ability to excrete it, but rather by our innate senses - sensory perception and biological feedback mechanisms. Both of these mechanisms are specific for every individual, just as water is.
For this reason, it is the very same folly to apply a "one size fits all" set of policy recommendations to salt consumption as it is for water consumption. Salt consumption is self-limiting and regulated by nature's biology, not by shortsighted dietary recommendations.
