1 Liz Gorson
Eight Glasses of Water A Day: Essential or Unnecessary?
Drink eight glasses of water per day to have “health benefits.” Communicated
from parents, school and fitness education teachers, and popular magazines, this advice is
far from its decline in conversation. A Google search on the topic prompts web pages
with numerous tips for consuming this daily amount. In fact, this guideline has become so
pervasive that it is frequently referred to just as the “8 x 8” rule, indicating that each glass
must be 8 ounces (Porter). Claims of advantages from consuming this amount of water
have ranged from kidney protection, preventing dehydration, and assisting weight loss.
Respected newspapers and publications have further promoted the extra intake of water,
including the New York Times article “For Lifelong Gains, Just Add Water. Repeat”
(Brody). With high school athletic coaches proclaiming “hydration, hydration,
hydration!” and individuals toting water bottles to various daily activities, drinking
water—one of the most basic human acts—nearly resembles a cultural trend. Although
consuming fluids is important to maintain the body’s homeostasis, a closer look at the
scientific examinations of the data that justifies the “8 x 8 rule” reveals mysterious
origins, skepticism from health professionals, and a lack of compelling evidence.
Perhaps the most prominent article igniting the controversy was Heinz Valtin’s
"Drink at Least Eight Glasses of Water a Day." Really? Is There Scientific Evidence for
"8 x 8"? (Tudish). Due to increasing doubt and suspicion from medical experts regarding
this issue, the American Journal of Physiology asked Valtin, an expert in the field, to
review existing studies (Tudish). As an author of multiple textbooks concerning water
balance and kidneys as well as a researcher for over four decades in the field, Valtin was
2 well suited for the position (Tudish). In 2002, he compiled a comprehensive, 10-month
study of the previous scientific literature. After analyzing procedures that used random
assignment in their experimental design and that were printed in peer-reviewed journals,
he found a lack of conclusive evidence supporting the recommendation (Valtin).
One of the missing pieces of the 8 x 8 rule that Valtin highlighted was the
obscurity of its origins. He believed a likely culprit could be a widely misinterpreted
1945 federal analysis (Tudish). In this report, the U.S. Food and Nutrition Board
recommended “1 milliliter of water for each calorie of food,” which would be equal to
roughly 64 – 80 ounces each day (Hale). However, another sentence explaining how this
fluid could also stem from food was lost in the dissemination (Hale). Other possible
contributors could be the Stillman Diet, also known as the Doctor’s Quick Weight Loss
Diet. Developed in 1967, this low carbohydrate, low fat method also advises the 8 x 8
rule (“Stillman Diet”). The Atkins diet, a well-known regimen established in 1972, also
emphasized eight glasses of water per day. During the Atkins Diet peak in 2003 and
2004, one out of eleven adults was attempting the approach (“Atkins Diet”). Although its
foundations were shaky, popular diet gurus advocating the 8 x 8 rule helped foster
widespread acceptance from the American public.
Despite the influence of popular opinion on many consumers’ fluid intake
choices, evaluations of scientific data simply do not clarify or document the benefits of
eight glasses of water per day. Valtin’s extensive research covered literature in electronic
publications, older print information, and dialogues with nutritionists who concentrate in
the area of thirst and fluid consumption (Valtin). More specifically, he found that both
seemingly healthy males and females clearly did not need this amount of water. Valtin
3 went even further to suggest that caffeinated beverages and light alcoholic drinks in
moderation could be included in the amount of fluid that we need each day (Valtin).
Valtin states: “Not only is there no scientific evidence that we need to drink that much,
but the recommendation could be harmful, both in precipitating potentially dangerous
hyponatremia and exposure to pollutants and also in making many people feel guilty for
not drinking enough” (Valtin). In addition to keeping track of fat and calories, counting
glasses of water per day could be unnecessarily laborious. The 8 x 8 rule is apparently too
strict in its wording to be applicable to the vast majority of people, and may even have a
negative effect on people who strive for this goal.
In addition to Valtin’s expose, numerous other popular articles and scientific
examinations question the necessity of drinking eight glasses of water each day. In an
article in the Journals of Gerontology in 2000 specifically regarding the elderly, a study
concluded that consuming eight glasses of fluids per day to improve any aspect of an
older individual’s health “seems to serve little useful purpose” and may actually be an
uncomfortable level of consumption for that person of that age group (Lindeman). In the
Journal of The American Society of Nephrology, another article stated that there is not
sufficient evidence that drinking more water leads to any clear, positive outcome; in fact,
the article states that there is a “lack of evidence in general” (Goldfarb). This
acknowledgment is in accordance with Valtin’s suggestion that the possibility of further
research could disprove his conclusion. Valtin’s verdict came from the lack of supporting
evidence rather than studies that explicitly weaken the 8 x 8 guideline. However, the
inadequacy of information justifying the claim may still be reason to be cautionary about
blindly following this traditional rule of thumb.
4 Although there seems to be a current broad scientific consensus about the lack of
supporting research pertaining to the 8 x 8 rule, dissenting voices persist in popular
culture. Ultimately, this standard has continued in our culture despite the publication of
contrary research a decade ago. For instance, The New York Times published an article
last year explaining the positive benefits of drinking 8 glasses of water per day for the
kidneys, while still recognizing the motto as being “widely considered a myth”
(O’Connor). The study referred to in the article followed over 2,000 men, and found that
after controlling for extraneous variables, those who drank the most fluids were least
likely to encounter decreases in kidney function (Clark). However, the New York Times
article seems to attribute this success rate particularly to drinking water. Furthermore, in a
newspaper opinion piece, the author describes a case in which consumption of eight
glasses of water per day helped rid him of his cough (Lawrence). Another newspaper
article also recommends keeping to the 8 glass of water per day rule. However, the article
did not mention a specific study; rather, it states: “Researchers say people who drink just
three glasses of water a day are five times more likely to get a blocked nose or sore throat
than those who drink the recommended eight.” (Davidson). This article’s claims rely on
research funded by Brita—a water filter company—creating possible conflicts of interest
in the research outcomes. This dissenting information seems to include funding conflicts
or unspecified claims.
There are several explanations why the 8 x 8 rule has persisted and could continue
in our cultural traditions. One reason may be the years of accumulated weight this
guideline has acquired. For some people, its establishment in common conversation leads
to a normalized habit that overcomes factual research. Another possibility, which Valtin
5 and other researchers raised in their analyses, is the difficulty of proving counterfactual
research. These studies did not find facts that clearly advise not to consume eight glasses
of water each day; they only discovered the lack of facts claiming the need to adhere to
this rule. If there is not enough research to say the 8 x 8 rule is sufficiently harmful to the
general public, consumers may continue to follow this recommendation. Lastly, a
conceivable boon to the rule is the plastic water bottle industry; mostly inexpensive and
convenient products combined with this easily accessible concept could facilitate a sales
boost. Although research condemning the mantra has been around for over a decade,
perhaps the 8 x 8 rule has maintained its popularity and prevalence in popular culture
simply because it seems intuitive and is easy to remember.
Health experts today offer several alternatives to rigorous water-drinking. Mayo Clinic, a
non-profit medical research group and popular online resource, recommends that people
drink water according to individual needs. “Although no single formula fits everyone,
knowing more about your body's need for fluids will help you estimate how much water
to drink each day. (“Water”). Therefore, other drinks, such as Gatorade and other sports
beverages, juices, and tea can also count for fluid intake. This website also accounts for
possible factors that may require extra water intake, including exercise, environment,
illness, and pregnancy, (“Water”). Research revealing the vague basis and lack of strong
evidence favoring the 8 x 8 rule suggests that it should not be applied universally as
general health guideline. This rule may be more appropriate for individuals who need
more water due to certain illnesses, exercise, and changes in climate. For the average
American consumer, drinking when one feels the sensation of thirst may be a more
appropriate measure of total amount of water to drink per day.
6 Works Cited
“Atkins Diet.” Everydiet. 7 October 2012. Web.
<http://www.everydiet.org/diet/atkins-diet>
Brody, Jane E. “For Lifelong Gains, Just Add Water. Repeat.” The New York Times. 11
Jul. 2000. < http://www.nytimes.com/2000/07/11/health/personal-health-forlifelong-gains-just-add-water-repeat.html?>
Clark, William F. “Urine Volume and Change in Estimate GFR in a Community-Based
Cohort Study.” Clinical Journal of the American Society of Nephrology. 6: 26342641. Nov. 2011. < http://www.asn-interactive.org/wpcontent/uploads/2011/11/CJASN-UrineVolumeArt.pdf>
Davidson, Lorraine. “Eight Glasses of Water a Day Can Help Prevent Flu.” The Daily
Mirror. 01 Dec. 2003.
<http://search.proquest.com.proxy.lib.umich.edu/docview/339246263?>
Goldfarb, Stanley. “Just Add Water.” Journal of the American Society of Nephrology.”
12 Mar. 2008.
<http://jasn.asnjournals.org/content/19/6/1041?ijkey=351a45ce754409ebec5c1f40
343f823a592559b0&keytype2=tf_ipsecsha&linkType=FULL&journalCode=jnep
hrol&resid=19/6/1041>
Hale, Jamie. “The Myth Behind Drinking 8 Glasses of Water a Day.” Psychcentral. 2010.
< http://psychcentral.com/blog/archives/2010/12/08/the-myth-behind-drinking-8glasses-of-water-a-day/>
7 Lawrence, Keith. “Eight Glasses of Water a Day Keep Side Effects Away” Messenger
Inquirer. 02 Feb. 2006.
<http://search.proquest.com.proxy.lib.umich.edu/docview/378378284>
Lindeman, Robert D. “Do Elderly Persons Need to be Encouraged to Drink More
Fluids?” The Journals of Gerontology. 55.7. Jul. 2000.
<http://search.proquest.com.proxy.lib.umich.edu/pqrl/docview/208625881/fulltex
t?accountid=14667>
O’Connor, Anahad. “The Claim: Drink Eight glasses of Water a Day to Protect the
Kidneys.” New York Times. Nov. 2011.
<http://well.blogs.nytimes.com/2011/11/07/really-the-claim-drink-eight-glassesof-water-a-day-to-protect-the-kidneys/>
Porter, Lisa. “What is the 8 x 8 Drinking Water Method?” Livestrong. Web. 19 Jul. 2010.
< http://www.livestrong.com/article/178969-what-is-the-8 x 8-water-drinkingmethod/>
Tudish, Catherine. “8 x 8 Study Prompts A Deluge In The Press (As Well As In Puns).”
Dartmouth Medicine. Trustees of Dartmouth College. 2012.
<http://dartmed.dartmouth.edu/fall02/html/vs_8study.shtml?>
“Stillman Diet.” Wikipedia. 28 Feb. 2012. < http://en.wikipedia.org/wiki/Stillman_diet>
Valtin, Heinz. ““Drink at Least Eight Glasses of Water a Day.” Really? Is There
Scientific Evidence for “8 x 8”?” American Journal of Physiology. 8 Aug. 2002.
8 <http://ajpregu.physiology.org.proxy.lib.umich.edu/content/283/5/R993.full?sid=
bc61e395-3e3e-4fbb-a1f5-06d8f06af291>
“Water. How Much Should You Drink Every Day?” Mayo Clinic. 10 Aug. 2012.
<http://www.mayoclinic.com/health/water/NU00283>