Water

[Guest guest]

I received this email recently and thought it might provoke some discussion

in our group as we generally suggest that people consume a lot of water to

maintain the status quo in our bodies. While I would agree that active

people should seek to replace the water we all lose through persperation,

exhalation and urinary output, this article seems to say that we have been

convinced to try to drink more than is required to do that and perhaps more

than is truly healthy.

Aubrey

Subject: From ABC News

No need to guzzle all that water, expert says

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 says

Newspaper articles, health and beauty magazines all advise drinking at least

8 full glasses of water a day totalling two litres for optimal health, an

approach called " 8x8 " by proponents.

But Dr Heinz Valtin of Dartmouth Medical School in New Hampshire says 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', " Dr Valtin said, who has written textbooks on the

subject of human water balance.

Writing in the American Journal of Physiology, Dr 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 millilitre of water for each

calorie of food eaten.

This adds up to two litres 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, " Dr

Valtin said.

" That system is so precise and so fast that I find it impossible to believe

that evolution left us with a chronic water deficit, " he 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, Dr

Valtin says.

He says thirst kicks in long before dehydration starts.

" It does it very quickly and very accurately and it does so in minutes, " Dr

Valtin said.

He says 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', " Dr

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, " Dr Valtin said.

" Persons with certain diseases must have large volumes of water - kidney

stones are probably the most common example, " he said.

The rest can just drink enough to slake thirst and this includes coffee, tea

and even beer, despite their diuretic effects, Dr Valtin says.

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.

" 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, " Dr Valtin said.

" Then there is the inconvenience of constant urination, the embarrassment of

having to go to the bathroom all the time, " he said.

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.