Drinking a lot of water is supposed to be healthy, but there is apparently little scientific support for the belief. A review of clinical studies has found no evidence that drinking eight glasses of water a day, the usual recommendation, is beneficial to a healthy person.
Numerous claims have been made about water — that it prevents headaches, removes dangerous “poisons,” improves the function of various organs and is associated with reduced risk for various diseases. But none of these is supported by scientific evidence. The authors were not even able to find a study leading to the “eight glasses a day” rule, whose origin remains unknown.
The researchers, in the June issue of The Journal of the American Society of Nephrology, say some studies have found evidence that drinking extra water helps the kidneys clear sodium, and long-term sodium retention might increase the risk of hypertension, but no clinical significance for the phenomenon has been established. Water also helps clear urea, but urea is not a toxin.
There is “intriguing” evidence that water might help decrease appetite and control weight gain, write the authors, who say this might be worth more research.
“Under normal circumstances,” said Dr. Stanley Goldfarb, a co-author and a professor of medicine at the University of Pennsylvania, “drinking extra water is unnecessary. I want to relieve people of the burden of schlepping water bottles around all day long.”
Showing posts with label water myth. Show all posts
Showing posts with label water myth. Show all posts
Monday, April 28, 2008
Sunday, April 6, 2008
The Benefits Of Water
Water Myths
Is bottled water better for you than tap? Or should you choose vitamin-enriched water over sparkling? Experts say, skip it all. None of these products are likely to make yoau any healthier. Below, we look at five major myths about the benefits of drinking water.
But first, how do you know if you're drinking enough water? Experts say there's an easy way to judge. If you're not thirsty, you're fluid intake is likely "just right."
Myth No. 1: Drink Eight Glasses Each Day
Scientists say there's no clear health benefit to chugging or even sipping water all day. So where does the standard advice of drinking eight glasses each day come from? "Nobody really knows," says Dr. Stanley Goldfarb, a kidney expert at the University of Pennsylvania.
Myth No. 2: Drinking Lots of Water Helps Clear Out Toxins
The kidneys filter toxins from our bloodstreams. Then the toxins clear through the urine. The question is, does drinking extra water each day improve the function of the kidneys?
"No," says Goldfarb. "In fact, drinking large amounts of water surprisingly tends to reduce the kidney's ability to function as a filter. It's a subtle decline, but definite."
Myth No. 3: Lots of Water Equals Healthier Skin
The body is already 60 percent water. So, if you take a 200-pound man, he's 120 pounds of water.
Adding a few extra glasses of water each day has limited effect. "It's such a tiny part of what's in the body," says Goldfarb. "It's very unlikely that one's getting any benefit." His full editorial is published in the current issue of the Journal of the American Society of Nephrology.
One study published in 2007 on the cosmetic benefit of drinking water suggests that 500 ml of water increases capillary blood flow in the skin. "But it's unclear whether these changes are clinically significant," says Goldfarb.
Myth No. 4: Drinking Extra Water Leads to Weight Loss
A more accurate statement may be: Drinking water is a helpful tool for dieters.
"Water is a great strategy for dieters because it has no calories," says Madeline Fernstrom of the University of Pittsburgh. "So you can keep your mouth busy without food and get the sense of satisfaction."
But water is not magical, she adds. Other zero-calorie options such as diet sodas are fine, too.
Myth No. 5: It's Easy to Get Dehydrated During a Workout
Dehydration sets in when a person has lost 2 percent of his or her body weight. So for a 200-pound man, this means losing 4 pounds of water.
Marathon runners, bikers and hikers all need to recognize the signs of dehydration. "It is also obvious that individuals in hot, dry climates have increased need for water," says Goldfarb.
The American College of Sports Medicine recommends that athletes drink 16 ounces of fluids a couple of hours before starting sports practice.
But for a stroll in the park, no water bottle is necessary. Goldfarb's advice: Just drink when you're thirsty.
Is bottled water better for you than tap? Or should you choose vitamin-enriched water over sparkling? Experts say, skip it all. None of these products are likely to make yoau any healthier. Below, we look at five major myths about the benefits of drinking water.
But first, how do you know if you're drinking enough water? Experts say there's an easy way to judge. If you're not thirsty, you're fluid intake is likely "just right."
Myth No. 1: Drink Eight Glasses Each Day
Scientists say there's no clear health benefit to chugging or even sipping water all day. So where does the standard advice of drinking eight glasses each day come from? "Nobody really knows," says Dr. Stanley Goldfarb, a kidney expert at the University of Pennsylvania.
Myth No. 2: Drinking Lots of Water Helps Clear Out Toxins
The kidneys filter toxins from our bloodstreams. Then the toxins clear through the urine. The question is, does drinking extra water each day improve the function of the kidneys?
"No," says Goldfarb. "In fact, drinking large amounts of water surprisingly tends to reduce the kidney's ability to function as a filter. It's a subtle decline, but definite."
Myth No. 3: Lots of Water Equals Healthier Skin
The body is already 60 percent water. So, if you take a 200-pound man, he's 120 pounds of water.
Adding a few extra glasses of water each day has limited effect. "It's such a tiny part of what's in the body," says Goldfarb. "It's very unlikely that one's getting any benefit." His full editorial is published in the current issue of the Journal of the American Society of Nephrology.
One study published in 2007 on the cosmetic benefit of drinking water suggests that 500 ml of water increases capillary blood flow in the skin. "But it's unclear whether these changes are clinically significant," says Goldfarb.
Myth No. 4: Drinking Extra Water Leads to Weight Loss
A more accurate statement may be: Drinking water is a helpful tool for dieters.
"Water is a great strategy for dieters because it has no calories," says Madeline Fernstrom of the University of Pittsburgh. "So you can keep your mouth busy without food and get the sense of satisfaction."
But water is not magical, she adds. Other zero-calorie options such as diet sodas are fine, too.
Myth No. 5: It's Easy to Get Dehydrated During a Workout
Dehydration sets in when a person has lost 2 percent of his or her body weight. So for a 200-pound man, this means losing 4 pounds of water.
Marathon runners, bikers and hikers all need to recognize the signs of dehydration. "It is also obvious that individuals in hot, dry climates have increased need for water," says Goldfarb.
The American College of Sports Medicine recommends that athletes drink 16 ounces of fluids a couple of hours before starting sports practice.
But for a stroll in the park, no water bottle is necessary. Goldfarb's advice: Just drink when you're thirsty.
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