Two kidney experts have taken it on themselves to dispel a handful of myths regarding water. Dr. Stanley Goldfarb and Dr. Dan Negoianu of the Renal, Electrolyte, and Hypertension Division at the University of Pennsylvania, Philadelphia reviewed several published clinical studies on the benefits of drinking a large amount of water daily, and found that there was little proof to back up the theories.
There are plenty of myths floating around about the benefits of drinking a lot of water, and some of these myths seem almost factual due to their popularity. The standard U.S. recommendation of 8 glasses of 8 oz of water per day is widely known, but there is little if any evidence to prove this beneficial.
Goldfarb and Negoianu agreed that some people, such as athletes or those that live in very dry, hot climates may require this much water to keep from being dehydrated, but for the average person, there is absolutely no evidence that drinking this quantity of water is beneficial.
Their study, which will be published in the June 2008 issue of the Journal of the American Society of Nephrology, may dispel many of the water-related myths.
Goldfarb insists that the sources of the “water myth” are the worlds of complementary and alternative medicine, and that the spread of the myth was propelled even further by the internet.
Goldfarb’s specialization in kidneys prompted he and Negoianu to review literature covering the benefits of drinking water, due to a common interest in the way the kidney handles fluids.
The pair deflated at least four popular myths during their research.
One myth, that drinking water reduces headaches, had only one study to back it up, and the results of the study lacked statistical significance.
A second myth, that increased water intake improves skin tone, is also not proven. While there is evidence that dehydration can affect the skin, Goldfarb said, “There are no data to suggest that it actually improves the content of the skin.”
It has also been claimed that filling up on water will assist in suppressing appetite. Many claim that if you drink enough water it can help fight obesity, or at least maintain weight more easily. “Many people drink water before and during the meal to try to suppress their appetite,” Goldfarb stated, yet there is “no consistent evidence” that water suppresses appetite. “Because you absorb water so quickly and it moves through the GI tract so quickly, it probably doesn’t fill you up the way people have proposed, nor does it lead to the release of hormones which suppress appetite as far as we know,” Goldfarb affirmed.
A fourth falsehood is that drinking a large quantity of water flushes toxins from the body and improves kidney functions. The kidney experts were quick to dispel this myth. No clinical evidence exists to back this up. Some have even claimed that water intake can benefit the function of organs; however no studies have documented this type of benefit either. Goldfarb plainly stated that this is not how the kidney works. “When you drink a lot of water you end up having a larger volume of urine but don’t necessarily increase the excretion of various constituents of the urine.” Sodium and urea might be expelled, but there is nothing to back up any clinical benefit to this.
Goldfarb says there is absolutely no rational basis for the “8×8 rule” and it is very unclear where this recommendation even began. Not only is there no evidence to back up extra water’s benefit, there are some circumstances where over-consumption may be unhealthy. “In long-distance runners, for example, more harm is done by long distance runners over-drinking during races than by long distance runners who under-drink,” Goldfarb explicated.
Goldfarb further clarified by citing the case of a woman who recently died when she developed brain swelling from continuously and rapidly drinking water for several minutes as part of a radio contest.
Despite a lack of evidence, the Food Standards Agency and others are sticking to their recommendations of drinking 6 to 8 glasses a day.
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