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There’s no evidence that we need to drink 8 glasses of water a day
sciencealert ^ | 25 AUG 2015 | FIONA MACDONALD

Posted on 09/26/2015 10:50:05 AM PDT by JoeProBono

Most of us have spent our lives feeling pressured by the notion that we need to drink at least eight glasses of water a day in order to avoid dehydration and stay healthy. But according to American paediatrician Aaron E. Caroll from Indiana University, there's absolutely no science to back this up, and there never was.

Caroll has already co-written a widely cited research paper and book debunking common health myths - primarily the idea that all humans need to drink eight 8-ounce (237 mL) glasses of water a day - but the rumour just won't go away, with an onslaught of media this year alleging that dehydration is on the rise due to children not drinking enough water. So Caroll took to The New York Times this week to clear things up once and (hopefully) for all.

"Contrary to many stories you may hear, there’s no real scientific proof that, for otherwise healthy people, drinking extra water has any health benefits," he writes. "For instance, reviews have failed to find that there’s any evidence that drinking more water keeps skin hydrated and makes it look healthier or wrinkle free."

So where did the great water myth come from? It's generally believed that the source is a 1945 Food and Nutrition Board Recommendation that declared, "a suitable allowance of water for adults is 2.5 litres daily in most instances. An ordinary standard for diverse persons is 1 millilitre for each calorie of food". As you might have guessed, 2.5 litres more or less works out to be around eight glasses. But what's usually ignored from that report is the crucial next sentence: "Most of this quantity is contained in prepared foods."

In fact, depending on your diet, there may be no reason to drink excess water at all. "Water is present in fruits and vegetables. It’s in juice, it’s in beer, it’s even in tea and coffee," writes Caroll. "Although I recommended water as the best beverage to consume, it’s certainly not your only source of hydration. You don’t have to consume all the water you need through drinks."

Before you object and tell us that coffee, tea, and alcohol dehydrate us, and therefore can't count towards our daily water intake, science has debunked that myth too.

A 2002 review by physician Heinz Valtin from Dartmouth University in the US found that not only was there no peer-reviewed evidence to support the eight glasses a day rule, there was also no research to suggest that other drinks couldn't be used to adequately hydrate us.

"This conclusion is supported by published studies showing that caffeinated drinks (and, to a lesser extent, mild alcoholic beverages like beer in moderation) may indeed be counted toward the daily total, as well as by the large body of published experiments that attest to the precision and effectiveness of the osmoregulatory system for maintaining water balance," Valtin concludes.

In the same study, he also broke down the myth that by the time we feel thirsty it's 'too late'. In reality, we feel thirsty exactly when we're supposed to: "when the concentration of blood (an accurate indicator of our state of hydration) has risen by less than 2 percent," he says, "whereas most experts would define dehydration as beginning when that concentration has risen by at least 5 percent.".........


TOPICS: Chit/Chat; Food; Science
KEYWORDS: water
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To: LostInBayport
I have yet to meet anyone that agrees with me that coffee is colored water

Oh no, they say ... there's salts and minerals and caffeine and ...

Yeah ... so ...


Colored, salty, mineralized colored water ... like Snapple .... or ... tea .... or .... Koolaid .... or ....


If I drink eight cups of coffee, did I or did I not drink eight cups of water .... with stuff in it ?

21 posted on 09/26/2015 11:14:04 AM PDT by knarf (I say things that are true ... I have no proof ... but they're true.)
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To: alloysteel

what do you mean by metabolizing your body tissue ?


22 posted on 09/26/2015 11:15:38 AM PDT by knarf (I say things that are true ... I have no proof ... but they're true.)
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To: JoeProBono

I’ve always been suspicious of that “eight glasses a day” thing. I’m 5’1” and 100 pounds. Should I drink the same amount of water as some strapping, six-foot person? It makes no sense.


23 posted on 09/26/2015 11:19:56 AM PDT by Nea Wood
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To: JoeProBono

http://www.cnn.com/2015/09/25/politics/rep-bob-brady-pope-francis-glass-water/


24 posted on 09/26/2015 11:21:47 AM PDT by Fido969
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To: JoeProBono

I’ve been drinking more water to help prevent a reoccurrence of kidney stones. It helps to keep the kidneys flushed. I also find it helps my brain function better if I am not dehydrated.


25 posted on 09/26/2015 11:24:06 AM PDT by bubbacluck (America 180)
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To: JoeProBono

One doctor?a pediatrician? And what med school did he attend that studied nutrition. Made know nothing about nutrition and prevention. The whole broken system is based on people being sick

They spend a lot of time and attention on debunking traditional medicine

I hire doctors only who will work with me.

If there’s an infection I stop them at antibiotics and ask how to cure it. If they know and that’s a lot of the time, I try that first and find out also when to quit trying and get on antibiotics. Permanent damage is stupid.

If they don’t know how to cure something why am I paying them? If they’re there just to sell mess and do the pharmaceutical company, why would I ask them about nutrition?


26 posted on 09/26/2015 11:25:08 AM PDT by stanne
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To: SkyDancer

“You receive moisture from all sorts/forms.”

At least a pot of coffee and a liter of diet soda per day - exceeding this often. These are my forms of ‘moisture’ to stay awake. You gotta do what you gotta do.


27 posted on 09/26/2015 11:25:36 AM PDT by pieceofthepuzzle
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To: knarf
If I drink eight cups of coffee, did I or did I not drink eight cups of water .... with stuff in it ?

It seems so simple, doesn't it? But to some people the coffeemaker magically transmogrifies the water into some strange, new creation...that is water no more...


28 posted on 09/26/2015 11:25:56 AM PDT by LostInBayport (When there are more people riding in the cart than there are pulling it, the cart stops moving...)
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To: JoeProBono

Makes me wonder. Why did we used to call a bottle/can opener a “church key”?


29 posted on 09/26/2015 11:26:58 AM PDT by TruthWillWin (The problem with socialism is that you eventually run out of other peoples money.)
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To: stanne

That got seriously autocorrected


30 posted on 09/26/2015 11:28:57 AM PDT by stanne
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To: JoeProBono

Must be drought related.


31 posted on 09/26/2015 11:29:50 AM PDT by ThomasThomas (Silence is golden , duct tape is silver. El silencio es oro, cinta del conducto es de plata.)
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To: JoeProBono

When I go overseas, the ONLY THING that I drink is beer, as it’s always cheaper than soda and usually cheaper than bottled water (except for large containers).

It works fine.


32 posted on 09/26/2015 11:31:07 AM PDT by BobL (REPUBLICANS - Fight for the WHITE VOTE...and you will win (see my 'profile' page))
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To: JoeProBono

33 posted on 09/26/2015 11:31:27 AM PDT by dfwgator
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To: JoeProBono

Without getting too much into the debate on how much we need, I will share something that will benefit people with asthma and sinus issues.

Drinking extra water *does* hydrate dry mucus membranes. If you are running a dry heat (like forced air electric), you will notice an improvement in your sinuses by drinking a little extra water. And dry membranes are more likely to pick up airborne viruses. Which is also why it is better not to keep your house too warm in the winter.

If you have a cold or flu, drinking extra water moistens your chest and makes it easier to move up mucus.

So, while there may be no need in general, there are circumstances where the extra water can be quite helpful.


34 posted on 09/26/2015 11:36:36 AM PDT by ChildOfThe60s (If you can remember the 60s, you weren't really there....)
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To: TruthWillWin

Most will admit that ‘church key’ is an odd name for something regularly used to get at a swig of beer. The earliest evidence of the phrase used in print is 1951, but stories about it date from 1935, which coincides with the time that beer was first sold in cans rather than just bottles. Pull tabs on cans didn’t appear until 1962, so the early beer cans required a tool of some kind to open. Nothing complicated—a flat but stout strip of metal with a sharp point which could be pressed into the top of the beer can to punch a triangular hole. This simple, easily made tool was immediately called a church key, taking the name of its predecessor, a bottle opener made of metal, with a round, oval or triangular open shape at one end to grip and pop off a bottle cap.

35 posted on 09/26/2015 11:36:47 AM PDT by JoeProBono (SOME IMAGES MAY BE DISTURBING VIEWER DISCRETION IS ADVISED;-{)
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To: Churchillspirit

That’s just it. When you drink so much liquid of any kind, you end up
going to the bathroom a lot. I’m up several times at
night; but I do get thirsty during the day until late
evening.


36 posted on 09/26/2015 11:37:33 AM PDT by Twinkie (John 3:16)
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To: Nea Wood

You should still drink eight glasses of water per day. Just drink smaller glasses. :) If you use shot glasses you could follow each one with a beer chaser.


37 posted on 09/26/2015 11:39:26 AM PDT by Purdue77 ("shall not be infringed")
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To: stanne

Aaron E. Carroll, MD, MS is a Professor of Pediatrics and Associate Dean for Research Mentoring at Indiana University School of Medicine. He is also the director of the Center for Health Policy and Professionalism Research. He earned a BA in chemistry from Amherst College, an MD from the University of Pennsylvania School of Medicine, and an MS in health services from the University of Washington, where he was also a Robert Wood Johnson Clinical Scholar.


38 posted on 09/26/2015 11:40:50 AM PDT by JoeProBono (SOME IMAGES MAY BE DISTURBING VIEWER DISCRETION IS ADVISED;-{)
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To: JoeProBono

Unless, of course, you work 10 hours a day under the hot sun, then 3 to 4 quarts of ice cold water are in order. Sun stroke is no fun and it can kill you.


39 posted on 09/26/2015 11:43:46 AM PDT by PIF (They came for me and mine ... now it is your turn ...)
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To: elcid1970

You need to be careful with consuming carbonated water, because it is shown to inhibit mineral absorption.

Remember, many people who over induldge in food are over fed and under nourished. Many times the body creates cravings to get nourishment, so to use water as a tool to limit food consumption, may be a bit shortsighted if you are not getting enough nutrients and absorbing them in your daily intake.

Water is very important to keep the heart from becoming inflamed, keep tendons and ligaments pliable, improve the health of skin, keep muscles and tissue free of harmful metabolic by products and improve cellular respiration. While fruit is another source of water, it is high in sugar content and a high consumption of fruit has been shown to raise triglycerides. It is a good practice to drink 6-8 ounces of water in the A.M with a 1/4 tsp of real salt or pink salt, to help improve electrolyte profile and prevent dehydration.


40 posted on 09/26/2015 11:44:19 AM PDT by mazz44
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