[R-G] [BillTottenWeblog] The Water Craze

[Bill Totten]

Lown RCTs (Random Clinical Thoughts)

Dr Bernard Lown, Founder and Chair, ProCor

www.procor.org (June 17 2008)

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Note: The true nexus of cardiovascular prevention lies at the
intersection of clinical medicine, basic science, social structure,
global economics, and public policy. No one I know can better navigate
that space than Dr Bernard Lown, ProCor s Founder and Chairman, who
consistently and powerfully has argued for a moral stance as the key
which unleashes action. The following essay is the first of a series by
Dr Lown titled "Lown RCTs: Random Clinical Thoughts". It is Dr Lown s
hope that these pieces will call attention to some of the deep
challenges encountered in medicine and will be relevant to health in
developing countries. We invite your responses and further discussion of
this thought-provoking article, which focuses on the essential and
elemental: water".
_____


I was taken aback when an elderly patient confessed dejectedly that she
didn t drink the eight glasses of water her physician had prescribed. I
was astounded to learn that water loading for all comers pervades
medical practice. But how robust is the scientific evidence and how did
this come about? Innovations in clinical practice are usually based on
accumulations of scientific breakthroughs. These are first published in
medical journals and then trumpeted 24/7 in the media. Yet I could not
recall a single scientific study on the benefits of increased water
consumption.

A systematic search of the medical literature turned up a blank.
Recently I came across comments of Dr Heinz Valtin, which stimulated me
to address this issue. Dr Valtin is an emeritus professor of physiology
at Dartmouth Medical School, an authority on kidney function and water
balance, on which subjects he has authored several textbooks. After an
exhaustive ten-month search of the literature, Dr Valtin likewise could
not identify a single published paper relating to daily water
requirements {1}.

Apparently, in the 1940s the Food and Nutrition Board of the Institute
of Medicine offered recommendations on food and water needs. As a rough
rule of thumb, it suggested drinking one milliliter of water for every
calorie eaten. This equals roughly two quarts or eight eight-ounce
glasses daily. An important proviso followed: "Much of this (water) can
be gathered from the food that we eat". So in fact, if one eats a
healthy diet, no additional water may be required.

The minimum daily requirement of liquid has been defined. Those residing
in moderate climates lose about 500 milliliters or sixteen ounces of
water daily. This is referred to as the obligatory fluid loss, and
includes water mandatorily excreted by kidneys, insensible water loss
from skin through evaporation, a well as water shed in tears, eliminated
in menstrual fluid, semen, and feces. Such losses are readily replaced
by the high content of water in solid food and by the fact that most
people consume beverages such as coffee, tea, fruit juices, wine, and
alcohol.

Is there any benefit though from additional fluid intake? A prevailing
notion is that drinking more water may help with constipation. But the
water one drinks is excreted by the kidneys, not by the intestines.
Another popular myth is that more water helps with weight loss. No
scientific evidence supports the greater efficacy of dieting when water
intake is increased. Nor does water dousing help combat kidney stones,
urinary tract infection, or bladder cancer.

 Could eight glasses of water daily inflict harm? As a physician, I have
been concerned with disruption of sleep by nocturia. Excess water
accentuates the physiological tendency to excrete more fluid when one is
recumbent during the night. Elderly males are especially predisposed to
nocturia. They invariably suffer from benign prostatic hypertrophy
(BPH), which sensitizes the bladder neck to spasm even when the bladder
stores modest amounts of urine. Being roused multiple times during the
night diminishes the restorative qualities afforded by sleep and may
play a role in the ubiquity of depression among the aged.

Another, but far less frequent, adverse consequence of excess water
intake is hyponatremia or water intoxication. It is rarely encountered
among elderly who are taking powerful diuretics, such as lasix. A
diuretic is commonly prescribed for largely innocuous, gravity-dependent
ankle swelling. When coupled with an eight-glasses-of-water regimen,
substantial dilution of body sodium may lead to adverse
neuropsychological effects.

So far I have evaded discussing how binging on water came about. In
fact, I do not know.  However, the innocent statement from the Food and
Nutrition Board of the Institute of Medicine, some sixty years ago, is
an unlikely source. Nor do I think the medical profession was a
significant actor in launching the practice. It took far more powerful
voices. Aggressive beverage marketers like Coca-Cola and PepsiCo are
more likely suspects. In the short span of a few years their water
brands, Aquafina and Dasani, became blockbuster successes.

The current market for bottled water is huge and growing. Revenues from
global soft drinks and bottled water sales this year are anticipated to
exceed US$146 billion. The US is the largest consumer in the world {2}.
This has led the Wall Street Journal to gush that bottled water is the
next best thing to oil and gold.

A variety of factors are driving demand. Topmost in my view is the
medicalization of every aspect of life and the erroneous view that we
are prone to dehydration unless constantly replenished. Additional
factors are the perception that bottled water is safer and tastier than
municipal water. In most industrialized countries, however, and
especially in the United States, tap water is far more stringently
regulated and more frequently monitored than bottled water. For example,
New York City has tested its water supply 430,000 times in a single year
{3}. Municipalities provide high-quality potable water. The sobering
fact is that 25% of bottled water, including popular brands such as
Aquafina and Dasani, are merely filtered tap water processed close to
their distribution point.

If bottled water is without health or safety advantage, wherein is its
popularity? When tap and bottled water are compared in blind tests, the
source is unidentifiable. The choice is therefore not driven by taste.
Perhaps the appeal relates to enhancing self-image. Carrying a small
bottle was pioneered by super-models to suggest elegance, high fashion,
and affluence. Marketing is particularly focused on women, who drink
more bottled water than men. Possibly, as with other articles of
consumption, the appeal is not related to the intrinsic utility of the
product but in the message it conveys. Being able to afford a product,
far costlier than tap water, proclaims wealth and success.

Indeed bottle water is very costly. Dasani and Aquafina sell for about
five US cents an ounce, while municipal water sells for less than one US
cent a gallon. Even gasoline, at current exorbitant prices, is forty
percent. Indeed bottled water puts Big Oil to shame.

I am persuaded that for those living in developed countries, drinking
bottled water should shame the user. Today a billion people lack
reliable access to safe drinking water. Dirty water spews disease.
According to the World Health Organization, unclean water accounts for
eighty percent of global disease and kills about five million people
annually. It is worth pondering that merely a quarter of the spending on
bottled water could provide safe sanitation and clean water for the
wretched of the earth.

Even for those who cannot muster a sense of charity for the afflicted,
self-interest should cause them to hesitate when resorting to bottled
water. Producing and transporting plastic bottles consumes prodigious
quantities of oil and other fossil fuels. Non-biodegradable plastic adds
to litter and solid waste, which crowds landfills. It has been estimated
that to produce the bottles that Americans consumed in 2006 required in
excess of seventeen million barrels of oil and increased global warming
by adding 2.5 million tons of carbon dioxide. That is why I embrace the
view of Tom Standage, author of the history of water and other drinks:
"Tap water is not so abundant in the developing world. And that is
ultimately why I find the illogical enthusiasm for illogical water not
simply peculiar, but distasteful."

The practicing physician ultimately needs to deal with the mundane
question of an individual patient, "How much water should I drink a
day?" Unfortunately this important question cannot be readily answered.
To respond concretely one must have a wealth of information. For
example, how does water requirement vary with age, with gender, with
level of activity, with composition of diet, with daily calorie intake,
with body mass index, with psychological stress, with type of
occupation, in pre- and post-menopausal women, with presence and type of
chronic ailments, on and on. A doctor does not treat humankind but a
specific unique person. To do so responsibly, one needs prodigious
amounts of sound evidence-based information.

The physician, dealing with problems of the here and now, cannot wait
for the definitive data. Uncertainty is the province of the
professional. Herein a complex synthesis is required of a sound
education in the basics, guided by a wealth of well assimilated
experience, restrained by knowledge that all actions have unintended
consequences, and chaperoned by solid common sense.

So what is my response to the simple water question? First, a sense of
thirst, though weakened by age, is a good litmus for fluid intake. Eight
ounces of liquid with a meal should suffice for those not running a
marathon or living in the tropics. If the urine is scanty and
concentrated, an extra eight ounces is advisable.

While diffident about the broad question of how much, I would not
hesitate being judgmental when it relates to bottled water and carting
it as though an indispensable amulet of healthy living. Bottled water is
not a medical but a moral issue. As Voltaire cautioned, "Those who make
us believe absurdities can make us commit atrocities". Resorting to
bottled water as a routine practice is indeed an atrocity against the
environment and against common sense.

References:

1. In the drink: Do we really need eight glasses of water a day?
Interview Professor Heinz Valtin. Nutrition Action Health Letter (June 2008)

2. http://www1.ibisworld.com/pressrelease/pressrelease.aspx?prid=124

3. Standage T. Bad to the last drop. Op Ed.  New York Times (August 01 2005)

4. Standage T. A History of the World in Six Glasses (2006)


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