Sunday, January 28, 2007

Do We Need 8 Glasses of Water A Day?

Okay, I'll admit I fell for this one. I bought into the hype that we all need 8 glasses of water a day or else we'll be chronically dehydrated. I think it's a pretty common misconception. Here's what the evidence shows:

"In an invited review published online by the American Journal of Physiology August 8, Valtin, the Vail and Hampers professor emeritus of physiology at Dartmouth Medical School, reports no supporting evidence to back this popular counsel, commonly known as "8 x 8" (for eight, eight-ounce glasses)."
Dartmouth Medical School News, August 8, 2002

So, where may this idea have come from?

The article continues:

"Valtin thinks the notion may have started when the Food and Nutrition Board of the National Research Council recommended approximately "1 milliliter of water for each calorie of food," which would amount to roughly two to two-and-a-half quarts per day (64 to 80 ounces). Although in its next sentence, the Board stated "most of this quantity is contained in prepared foods," that last sentence may have been missed, so that the recommendation was erroneously interpreted as how much water one should drink each day."

The big question for me is why do we fall for this stuff? Why do we accept this type of information as fact without any real evidence to back it up? A great response to this was given by a Los Angeles Times reader as quoted on Snopes, the urban legends reference website, regarding this topic:

"The advice fully meets three important criteria for being an American health urban legend: excess, public virtue, and the search for a cheap "magic bullet"."

It still floors me how gullible I've been and how much wishful thinking has permeated just about every facet of my life. *sigh*

tall penguin


Anonymous said...

Hey E-A,

A book for you to check out:

"You're not Sick, You're Thirsty"

tall penguin said...

I read that book at one point. You'll notice that it's referenced in the Snopes article I linked to.

For some comments on the author of that book, F. Batmanghelidj, and his "research" check out:

tall penguin

Jessica said...

Amazing how medical advice becomes misconstrued and then is pushed on everyone by the same medical community that published the original (correct) information. Makes you wonder how many other recommendations are based on false or misread information.

tall penguin said...

"Makes you wonder how many other recommendations are based on false or misread information."

This is what makes my head spin.

tall penguin

zoya said...

OK, I understand the case in point: misleading and misconstrued information. Let's set that aside for a moment. And I am only speaking from my experience on this. Eight glasses of water a day DO make a difference. I went for 27 years not drinking enough, and another 7 drinking much more. And it works - I am not so tired, stopped having headaches and don't need to eat when I am stressed. I knew nothing about the FDA recommendations for a few months after I first started drinking about 2 liters of water a day.

And yes, I realize that water was just an example. I thought I'd say this anyway.

Anonymous said...

I don't believe anything I read on quackwatch! That place is full of quacks!

tall penguin said...


Thanks for your experience.

My intention in bringing up this subject was not to say that we don't need to drink water or that it's not beneficial. The point for me is how information can be misunderstood and shared and eventually become such a part of our thinking that we don't even question it.

Whenever we think we've found a "miracle cure" we need to exercise caution and check out the facts, do the research and see what's really accurate.

I also want to bring people's attention to the common fault in thinking that we all have: we prefer stories to statistics. When someone tells us they've found something (even high doses of water) that changed their lives or that improved their health, we are much more likely to accept that story as fact, rather than see if there's any evidence for the statement made.

I have been personally gullible in this regard, having spent much time, money and effort pursuing every recommendation people would make for my health. "Try this." "See this practitioner." "Do this, you'll feel better." If I'd only done more research I would've saved myself a lot of grief.

tall penguin

tall penguin said...

Hi Anon,

I'm guessing you're joking. If not, I'd love to hear your comments on the "quacks" at quackwatch.

tall penguin

Anonymous said...

Hi E-A,

I tried to post the first message with my name but it didn't work, so I had to post as anon..

I honestly don't have time to write a long comment on this quackwatch stuff, but if you want to talk about it we can go out for coffee some day.

All I can say is that the information on quackwatch is not accurate in many cases, and the way they quote studies is often only a fraction of the truth. They take small paragraphs out of a massive study to try to prove their point.