Ttoommll
Tue, Aug-13-02, 05:59
No need to guzzle all that water, expert says
By Maggie Fox
WASHINGTON, Aug 9 (Reuters) - Trying to do the "right" thing
by drinking eight full glasses of water a day may do little
more than make a person run to the bathroom, a researcher said
on Friday.
Newspaper articles, health and beauty magazines all advise
drinking at least 8 full glasses of water a day totalling 64
ounces (two litres) for optimal health -- an approach called
"8x8" by proponents.
But Dr. Heinz Valtin of Dartmouth Medical School in New
Hampshire said there is no scientific evidence to back up
this advice, which has helped create a huge market for
bottled water.
"After 10 months of careful searching I have found no
scientific evidence that supports '8x8'," Valtin, who has
written textbooks on the subject of human water balance, said
in a telephone interview.
Writing in the American Journal of Physiology, Valtin, a
kidney specialist, said people forget that the food they eat
also contains some water.
The Food and Nutrition Board of the National Research Council
has recommended that people take in about one milliliter of
water for each calorie of food eaten.
This adds up to two liters, or 74 fluid ounces on an average
2,000-calorie diet. But the National Research Council also
noted that much of this is already contained in food.
"I did 43 years of research on that system -- the
osmoregulatory system. That system is so precise and so fast
that I find it impossible to beleve that evolution left us
with a chronic water deficit," Valtin said.
LOW ON FLUID
If a person gets low on fluid, the body compensates by
bringing fluid back out of the kidneys and by slowing the loss
of water through the skin, Valtin said. Thirst kicks in long
before dehydration starts, he added.
"It does it very quickly and very accurately and it does so in
minutes," Valtin said.
He said he and colleagues became concerned after seeing dozens
of newspaper and magazine articles urging people to sip water
all day. "I started talking to my colleagues and asking them
'Do you know of any evidence for this?'. Invariably, they
said, 'No I think it's a myth'," Valtin said.
The journal asked him to review all the scientific studies he
could find and he concluded that someone misinformed has been
telling people to drink large amounts of water when most do
not need to.
"I am referring to healthy adults in a temperate climate
leading a largely sedentary existence," Valtin said. "Persons
with certain diseases must have large volumes of water --
kidney stones are probably the most common example."
The rest can just drink enough to slake thirst -- and this
includes coffee, tea, and even beer -- despite their diuretic
effects, Valtin said.
He hopes people will be relieved of the guilt of not getting
enough water, and of the expense of buying bottled water to
drink throughout the day.
poster's note -- "relieved of the GUILT"? <chuckle>
"There is also the possibility that if you drink a lot of
water that happens to be polluted then of course you get more
pollutants," Valtin said.
"Then there is the inconvenience of constant urination, the
embarrassment of having to go to the bathroom all the
time," he added.
And overdoses of water can cause water intoxication that can
lead to confusion and even death. Water intoxication is one
deadly effect of taking the drug Ecstasy, for instance,
because it makes people thirsty beyond their physical needs.
-----------------------------------------------
poster's note -- Didn't know that. I thought it was the
opposite, that Ecstasy raised metabolism and body temperature,
causing sweating and you had to drink more water or die, but
then, I don't know jack about Ecstasy. By "water intoxication"
I assume he means you urinate out your mineral stores, am I
correct or even close?
Tom
By Maggie Fox
WASHINGTON, Aug 9 (Reuters) - Trying to do the "right" thing
by drinking eight full glasses of water a day may do little
more than make a person run to the bathroom, a researcher said
on Friday.
Newspaper articles, health and beauty magazines all advise
drinking at least 8 full glasses of water a day totalling 64
ounces (two litres) for optimal health -- an approach called
"8x8" by proponents.
But Dr. Heinz Valtin of Dartmouth Medical School in New
Hampshire said there is no scientific evidence to back up
this advice, which has helped create a huge market for
bottled water.
"After 10 months of careful searching I have found no
scientific evidence that supports '8x8'," Valtin, who has
written textbooks on the subject of human water balance, said
in a telephone interview.
Writing in the American Journal of Physiology, Valtin, a
kidney specialist, said people forget that the food they eat
also contains some water.
The Food and Nutrition Board of the National Research Council
has recommended that people take in about one milliliter of
water for each calorie of food eaten.
This adds up to two liters, or 74 fluid ounces on an average
2,000-calorie diet. But the National Research Council also
noted that much of this is already contained in food.
"I did 43 years of research on that system -- the
osmoregulatory system. That system is so precise and so fast
that I find it impossible to beleve that evolution left us
with a chronic water deficit," Valtin said.
LOW ON FLUID
If a person gets low on fluid, the body compensates by
bringing fluid back out of the kidneys and by slowing the loss
of water through the skin, Valtin said. Thirst kicks in long
before dehydration starts, he added.
"It does it very quickly and very accurately and it does so in
minutes," Valtin said.
He said he and colleagues became concerned after seeing dozens
of newspaper and magazine articles urging people to sip water
all day. "I started talking to my colleagues and asking them
'Do you know of any evidence for this?'. Invariably, they
said, 'No I think it's a myth'," Valtin said.
The journal asked him to review all the scientific studies he
could find and he concluded that someone misinformed has been
telling people to drink large amounts of water when most do
not need to.
"I am referring to healthy adults in a temperate climate
leading a largely sedentary existence," Valtin said. "Persons
with certain diseases must have large volumes of water --
kidney stones are probably the most common example."
The rest can just drink enough to slake thirst -- and this
includes coffee, tea, and even beer -- despite their diuretic
effects, Valtin said.
He hopes people will be relieved of the guilt of not getting
enough water, and of the expense of buying bottled water to
drink throughout the day.
poster's note -- "relieved of the GUILT"? <chuckle>
"There is also the possibility that if you drink a lot of
water that happens to be polluted then of course you get more
pollutants," Valtin said.
"Then there is the inconvenience of constant urination, the
embarrassment of having to go to the bathroom all the
time," he added.
And overdoses of water can cause water intoxication that can
lead to confusion and even death. Water intoxication is one
deadly effect of taking the drug Ecstasy, for instance,
because it makes people thirsty beyond their physical needs.
-----------------------------------------------
poster's note -- Didn't know that. I thought it was the
opposite, that Ecstasy raised metabolism and body temperature,
causing sweating and you had to drink more water or die, but
then, I don't know jack about Ecstasy. By "water intoxication"
I assume he means you urinate out your mineral stores, am I
correct or even close?
Tom