Water-Drinking Myth?
mike
>How did the obsession start? Is there any scientific evidence that
>supports the recommendation?
Maybe excessive water consumption and subsequently polyuria are controls
for blood sugar level? Then we could implicate an insulin link:
http://www.sciam.com/article.cfm?articleID=00019760-09C1-1C5E-B882809EC588
ED9F&pageNumber=1&catID=1
Effect on the postprandial glycaemic level of the addition of water to a
meal ingested by healthy subjects and type 2 (non-insulin-dependent)
diabetic patients.
Torsdottir I, Andersson H.
Department of Clinical Nutrition, University of Goteborg, Sahlgren's
Hospital, Sweden.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_
uids=2759361&dopt=Abstract
Just an idea.Type 2 diabetics have increased thirst and pee more.This
is an adaptive response to control excess blood sugar.Does it work the
same in nondiabetics? Got me.
Steve Harris
news:aj1vu3$esl$4...@ins22.netins.net...
Glucose in the blood above renal pump theshholds is an osmotic diuretic--
this has nothing to do with insulin. It's just a simple effect of high blood
sugars on the kidneys.
Far from controlling excess blood sugar, this process generally makes it
worse, since you lose water faster than sugar, and you have to drink like
mad to keep up with the water loss.
In type II diabetes it's true you can generally hold your blood sugar down
to medium high (somewhere between normal and sky high) this way so long as
you're conscious-- but get behind at all, and you dehydrate, and then your
sugars go WAY up. That's basically what puts untreated type II diabetics in
coma-- dehydration.
SBH
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Eric Bohlman
> Just an idea.Type 2 diabetics have increased thirst and pee more.This
> is an adaptive response to control excess blood sugar.Does it work the
> same in nondiabetics? Got me.
Nope. Glomerular filtration of glucose (in more than minute quantities)
doesn't occur until blood glucose hits the individual's renal threshold,
which is usually around 200 mg/dl (11.1 mmol/L). Non-diabetics don't ever
get into that range, and neither do well-controlled diabetics.
Ian Goddard
>>Despite the dearth of compelling evidence, then, What's the harm?
>>"The fact is that, potentially, there is harm even in water,"
>>explains Valtin. Even modest increases in fluid intake can result in
>>"water intoxication" if one's kidneys are unable to excrete enough
>>water (urine).
>
>Modest increases?? Water intoxication?? Please post references for
>this claim. It is my understanding that water intoxication requires
>massive quantities of waters (several gallons in a day) and that
>normal kidneys could handle large amounts of water simply by excreting
>it. Of course if you are talking about impaired renal function or
>other factors (drug use) then less water may cause a problem.
IAN: The following abstract from Military Medicine indicates
that death by water intoxication occurs at levels of ingestion
between 10-20 liters (2.64 - 5.28 gallons) of water in a few
hours. That matches your observation. However, this source
states that guidelines define safe water intake during heavy
sweating at 1 to 1.5 liters (1.06 to 1.6 quarts) per hour.
Mil Med 2002 May;167(5):432-4
Death by water intoxication.
Gardner JW.
Office of the Armed Forces Medical Examiner, Armed Forces Institute of
Pathology, Rockville, MD 20850, USA.
With recent emphasis on increased water intake during exercise for the
prevention of dehydration and exertional heat illness, there has been
an increase in cases of hyponatremia related to excessive water
intake. This article reviews several recent military cases and three
deaths that have occurred as a result of overhydration, with resultant
hyponatremia and cerebral edema. All of these cases are associated
with more than 5 L (usually 10-20 L) of water intake during a period
of a few hours. The importance of maintaining adequate hydration in
exertional heat illness prevention cannot be overemphasized, but
excessive fluid intake may lead to life-threatening hyponatremia.
Current guidelines provide safety by limiting fluid intake during
times of heavy sweating to 1 to 1.5 L per hour.
PMID: 12053855 [PubMed - indexed for MEDLINE]
> Such instances are not unheard of, and they have led
>>to mental confusion and even death in athletes, in teenagers after
>>ingesting the recreational drug Ecstasy, and in ordinary patients.
>
>References please for this occurring with modest increases in water
>intake.
IAN: There were a number of other references at PubMed including
related to Ecstasy, one of which (PMID: 11499262) stated that a
fatal hyponatraemia occurred after a "large volume" of fluid was
consumed, which, to your point, does not sound like it matches a
"modest increase." The article in question from Dartmouth should
have been more precise when it made the claim: "Even modest
increases in fluid intake can result in 'water intoxication.'"
My quick search didn't find mild intoxication water levels, but
the guidelines above suggest it may be just above 1 - 1.5 L/hr.
"To lengthen thy life, lessen thy meals." Benjamin Franklin
Caloric Restriction: http://users.erols.com/igoddard/cr.htm
ada
that one consumes (including in food items)in the course of the day,
then he has a point. However, I have always understood the 層ater
formula' recommendation to be vs.the sugar-laden beverages that
basically qualify to be in the dessert/candy category as this health
news item from Tufts suggests.
"Popular Summer Drinks Called Desserts in Disguise"
http://story.news.yahoo.com/news?tmpl=story2&cid=594&ncid=594&e=11&u=/nm/20020809/hl_nm/diet_beverages_dc_1
ada
Tsu Dho Nimh
>http://www.dartmouth.edu/dms/news/2002_h2/08aug2002_water.shtml
>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.
Also, many diet plans involve drinking plenty of water. It
causes a feeling of fullness.
>Valtin emphasizes that his conclusion is limited to healthy adults
>in a temperate climate leading a largely sedentary existence --
>precisely, he points out, the population and conditions that the "at
>least" in 8 x 8 refers to. At the same time, he stresses that large
>intakes of fluid, equal to and greater than 8 x 8, are advisable for
>the treatment or prevention of some diseases, such as kidney stones,
>as well as under special circumstances, such as strenuous physical
>activity, long airplane flights or hot weather.
Tsu Dho Nimh
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This message has been modified from its original version.
It has been formatted to fit your brain.
Tsu Dho Nimh
>Mil Med 2002 May;167(5):432-4
>Death by water intoxication.
>Gardner JW.
>With recent emphasis on increased water intake during exercise for the
>prevention of dehydration and exertional heat illness, there has been
>an increase in cases of hyponatremia related to excessive water
>intake. This article reviews several recent military cases and three
>deaths that have occurred as a result of overhydration, with resultant
>hyponatremia and cerebral edema. All of these cases are associated
>with more than 5 L (usually 10-20 L) of water intake during a period
>of a few hours.
That's 2-5 GALLONS of water in a couple of hours. Definitely
enough to kill you, and far from a "modest increase". 64 ounces
of water, spread across the day, unless you have something
dreadfully wrong with your kidneys, is not going to do much to
you.
Ian Goddard
>igod...@erols.mom (Ian Goddard) wrote:
>
>>Mil Med 2002 May;167(5):432-4
>>Death by water intoxication.
>>Gardner JW.
>
>>With recent emphasis on increased water intake during exercise for the
>>prevention of dehydration and exertional heat illness, there has been
>>an increase in cases of hyponatremia related to excessive water
>>intake. This article reviews several recent military cases and three
>>deaths that have occurred as a result of overhydration, with resultant
>>hyponatremia and cerebral edema. All of these cases are associated
>>with more than 5 L (usually 10-20 L) of water intake during a period
>>of a few hours.
>
> That's 2-5 GALLONS of water in a couple of hours. Definitely
>enough to kill you, and far from a "modest increase".
IAN: Which is why I said: "The following abstract from Military
Medicine indicates that death by water intoxication occurs at
levels of ingestion between 10-20 liters (2.64 - 5.28 gallons)
of water in a few hours. That matches your observation." Rich's
observation being that a "modest increase" is an understatement.
Tim Tyler
:>>explains Valtin. Even modest increases in fluid intake can result in
:>>"water intoxication" if one's kidneys are unable to excrete enough
:>>water (urine).
However if you have functional kidneys, the chances are that more water
will be good for you.
A relevant book:
Your Body's Many Cries for Water, by Fereydoon Batmanghelidj
http://www.amazon.com/exec/obidos/ASIN/0962994235/
--
__________
|im |yler http://timtyler.org/ t...@tt1.org
David Wright
>:>>"The fact is that, potentially, there is harm even in water,"
>:>>explains Valtin. Even modest increases in fluid intake can result in
>:>>"water intoxication" if one's kidneys are unable to excrete enough
>:>>water (urine).
>
>However if you have functional kidneys, the chances are that more water
>will be good for you.
>
>A relevant book:
>
>Your Body's Many Cries for Water, by Fereydoon Batmanghelidj
>
>http://www.amazon.com/exec/obidos/ASIN/0962994235/
A relevant comment on the foregoing silly book (and the '8 glasses a
day' myth):
http://www.snopes.com/toxins/water.html
-- David Wright :: alphabeta at prodigy.net
These are my opinions only, but they're almost always correct.
"If I have not seen as far as others, it is because giants
were standing on my shoulders."
Carey Gregory
> http://www.snopes.com/toxins/water.html
Dead link, try this one http://www.snopes.com/toxins/water.htm
Thomas Carter
>
> >How did the obsession start? Is there any scientific evidence that
> >supports the recommendation?
>
> Maybe excessive water consumption and subsequently polyuria are controls
> for blood sugar level? Then we could implicate an insulin link:
> http://www.sciam.com/article.cfm?articleID=00019760-09C1-1C5E-B882809EC588
> ED9F&pageNumber=1&catID=1
>
> Effect on the postprandial glycaemic level of the addition of water to a
> meal ingested by healthy subjects and type 2 (non-insulin-dependent)
> diabetic patients.
> Torsdottir I, Andersson H.
> Department of Clinical Nutrition, University of Goteborg, Sahlgren's
> Hospital, Sweden.
>
> http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_
> uids=2759361&dopt=Abstract
>
Thanks, Mike, for injecting some useful facts into this thread.
The evidence for a substantial benefit of drinking a lot of water is
sparce, but the evidence for a detriment is non existent. I guess it
can be termed non existent when billions drink it daily and a few
soldiers who who drink very excessive amounts die each decade from
hyponatremia. I see the drinking of a lot of water as having perhaps
the BEST benefit to risk ratio of any easy intervention available to
humans. The first paper in my archives shows a 54% reduction in CVD
fatalities for men who drink 5 glasses a day or more. Presumeably they
drank it with meals and had this benefit in spite of a 68% increase in
their post prandial spike which is seen in my eighth paper and the
paper Mike quoted above. They other evidence I have is more indirect
but well supports the large epidemiological study (1).
The post prandial spike in glucose levels is now thought by many
to be more dangerous than the fasting glucose levels themselves. See a
rather thourough article at:
http://www.medscape.com/SMA/SMJ/2001/v94.n08/smj9408.01.bell/smj9408.01.bell-01.html
Thanks to Mike's post I will now drink my 8 glasses of water between
meals, (somehow) and hopefully better control my glucose and insulin
levels which are getting to be thought of as more important to aging
every year.
This is from my records.
DEF: Water: should take 8 glasses a day to prevent oxidative damage.
It washes out free radicals? Or dilutes them? Or what?
Water intake of five or more vs. two or fewer glasses of water daily
is associated with a .46 relitive risk of fatal coronary heart disease
in men and a .59 rr in women.(1) A good part of this benefit seams to
be due to the replacement of other beverages by water.(1) Water
consumption decreases Hematocrit (5),(6),(7), which is associated with
decreased CVD mortality,(3),(4) and controls body temp. (7). Body
temp. is hypothesized be some, ie Roy Walford, to influence aging.
(1) Am J Epidemiol 2002 May 1;155(9):827-33
Water, Other Fluids, and Fatal Coronary Heart Disease The Adventist
Health Study
Jacqueline Chan1,2, Synnove F. Knutsen1,3, Glen G. Blix2, Jerry W.
Lee2 and Gary E. Fraser1,3
1 Adventist Health Studies, School of Public Health, Loma Linda
University, Loma Linda, CA.
2 Department of Health Promotion and Education, School of Public
Health, Loma Linda University, Loma Linda, CA.
3 Department of Epidemiology, School of Public Health, Loma Linda
University, Loma Linda, CA.
Whole blood viscosity, plasma viscosity, hematocrit, and fibrinogen
are considered independent risk factors for coronary heart disease and
can be elevated by dehydration. The associations between fatal
coronary heart disease and intake of water and fluids other than water
were examined among the 8,280 male and 12,017 female participants aged
38–100 years who were without heart disease, stroke, or diabetes
at baseline in 1976 in the Adventist Health Study, a prospective
cohort study. A total of 246 fatal coronary heart disease events
occurred during the 6-year follow-up. High daily intakes of water
(five or more glasses) compared with low (two or fewer glasses) were
associated with a relative risk in men of 0.46 (95% confidence
interval (CI): 0.28, 0.75; p trend = 0.001) and, in women, of 0.59
(95% CI: 0.36, 0.97). A high versus low intake of fluids other than
water was associated with a relative risk of 2.47 (95% CI: 1.04, 5.88)
in women and of 1.46 (95% CI: 0.7, 3.03) in men. All associations
remained virtually unchanged in multivariate analysis adjusting for
age, smoking, hypertension, body mass index, education, and (in women
only) hormone replacement therapy. Fluid intake as a putative coronary
heart disease risk factor may deserve further consideration in other
populations or using other study designs PMID: 11978586
11-10-1998
DRINKING WATER PREVENTS HEART ATTACK AND STROKE
30,391 healthy people with no prior history of heart disease, diabetes
or stroke were followed for 6 years.5 or more glasses of water per day
was associated with a 51% decrease in fatal heart attack, compared
with those who drank 2 glasses per day or less.
3,809 people with a prior history of coronary heart disease, diabetes
or stroke were also studied for 6 years.5 or more glasses of water per
day was associated with a 44% decrease in the incidence of fatal
stroke.
Nonfatal heart attacks and strokes were also reduced to a somewhat
lesser extent.
This benefit was seen only with water and not with other beverages.
(Note: Most municipal water supplies are heavily treated with
chemicals and are best purified before consumption, EMC)Chan J,
Synnove SF. Presentation at the 20th Congress of the European Society
of Cardiology, Vienna, Austria, 1998. (From the Department of
Epidemiology, Loma Linda University Medical School, Callifornia).
This seems to be another slant on the same study
(2) FROM REUTER’S HEALTH
Her death prompted a British parliamentary committee to issue a report
urging airlines to warn passengers of the risks of developing the
potentially fatal blood clots.DRINK WATER, NOT ALCOHOL
While researchers differ on whether long flights increase the risk of
blood clot formation, Makino said passengers, whether in economy or
first-class, should take precautionary measures such as drinking water
to prevent dehydration--one cause of blood clots.
Makino said the 25 deaths reported since his clinic opened in 1992
were not limited to economy class passengers. One was a US airline
pilot who collapsed in the cockpit after arriving in Tokyo.
``The syndrome may have become well-known only recently, but it has
been around ever since people began flying,'' Makino said. ``It's
wrong to assume that it is limited to economy class passengers,'' he
said.
Many of those who suffered serious cases were overweight passengers
and the elderly, he said. The average age of those who died was 64,
but one was just 46.
(3) Am Heart J 1994 Mar;127(3):674-82 Hematocrit and the risk of
cardiovascular disease--the Framingham study: a 34-year follow-up.
Gagnon DR, Zhang TJ, Brand FN, Kannel WB. Boston University School of
Public Health, Department of Epidemiology and Biostatistics, MA 02118.
We examined the relationship between the risk of CVD mortality and
morbidity and HCT over a period of 34 years of follow-up in the 5209
men and women in the Framingham cohort. There was an increased risk of
all-cause death as well as morbidity and mortality due to CVD in
subjects with HCT values in the highest quintile. There was no
evidence of a decrease risk of CVD in men with lower than median HCT
values, and women actually showed increased risk of CVD events with
lower HCT values, indicating a J- or U-shaped relationship between HCT
and CVD events. The impact of HCT on CVD events appears to differ for
different age groups and by sex. HCT is significantly related to the
incidence of CVD, including CHD, MI, angina pectoris, stroke, and IC
in younger men. In younger women, HCT is related to the incidence of
CVD, CHD, MI and mortality from CVD and CHD. A negative association
with CHF incidence and stroke death is noted in elderly women. These
results support the hypothesis that HCT is an important risk factor
for some CVD events, an association that merits further investigation.
PMID: 8122618
(4)
Am Heart J 2001 Oct;142(4):657-63 Hematocrit and the risk of coronary
heart disease mortality. Brown DW, Giles WH, Croft JB. Cardiovascular
Health Branch, Division of Adult and Community Health, National Center
for Chronic Disease Prevention and Health Promotion, Centers for
Disease Control and Prevention, Atlanta, GA 30341-3717, USA.
BACKGROUND: An association between hematocrit (Hct) and coronary heart
disease (CHD) mortality has been previously observed. However, the
relationship of Hct and CHD independent of other cardiovascular
disease (CVD) risk factors and differences between men and women
remain unclear. METHODS: We examined the association between Hct and
CHD mortality with Cox regression analyses of data from 8896 adults,
aged 30-75 years, in the Second National Health and Nutrition
Examination Survey (NHANES II) Mortality Study (1976-1992). Covariates
included age, sex, race, education, smoking status, hypertensive
status, total serum cholesterol, body mass index, white blood cell
count, and history of CVD and diabetes. Hct was categorized by use of
sex-specific tertiles, and all analyses were stratified by sex.
RESULTS: During 16.8 years of follow-up, there were 545 (men 343,
women 202) deaths from CHD (International Classification of Diseases,
9th revision [ICD-9] 410-414), 778 (men 426, women 279) deaths from
diseases of the heart (ICD-9 390-398, 402, 404, 410-414, 415-417,
420-429), and 2046 (men 1216, women 830) all-cause deaths. Among men,
the crude CHD mortality rate per 10,000 population was 42.6, 31.9, and
46.3 among those with Hct in the lower, middle, and upper tertiles,
respectively. The corresponding crude CHD mortality rates among women
were 12.6, 18.6, and 27.7. After adjustment for age and other CVD risk
factors, there was no association between Hct in the upper tertile
compared with the lower tertile and mortality from either CHD,
diseases of the heart, or all causes among men. Women with Hct in the
upper tertile were 1.3 times (95% CI 0.9-1.9) more likely to die from
CHD than were women with Hct in the lowest tertile, after multivariate
adjustment. The effect of high Hct on CHD mortality among women
younger than 65 years of age was slightly stronger (relative risk 2.2,
95% CI 1.0-4.6). CONCLUSIONS: These results suggest that the
association between Hct and mortality from CHD and all causes is
complex, differing both by sex and age. Further research is needed to
gain a better understanding of these age and sex differences. PMID:
11579356
(5) Pflugers Arch 2001 Jun;442(3):362-8 Water drinking causes a
biphasic change in blood composition in humans. Endo Y, Torii R,
Yamazaki F, Sagawa S, Yamauchi K, Tsutsui Y, Morikawa T, Shiraki K.
Department of Physiology, School of Medicine, University of
Occupational and Environmental Health, Kitakyushu, Japan. To
investigate precisely the fluid shifts associated with water drinking
in humans, we measured continuously blood density and plasma
electrolyte concentrations using the mechanical oscillator technique
and ion-selective electrodes, respectively, in healthy young
volunteers before (10 min) and after (48 min) water drinking for a
period of 2 min. Beat-by-beat blood pressure was also monitored
throughout the experiment. Drinking 1 l tap water caused a transient
increase in blood density immediately after the drinking episode (from
1051.1+/-0.5 g/l before drinking to 1051.8+/-0.5 g/l 4 min after the
start of drinking, P<0.05), followed by a gradual reduction
(1050.1+/-0.5 g/l at 31 min). This drinking-induced change paralleled
those of haematocrit, plasma density and plasma volume. Plasma [Na+]
and [Cl-] and osmolality decreased after drinking without transient
increases and reached minima at about 30 min. A transient increase in
mean arterial blood pressure was observed prior to the increase in
blood density. These findings suggest that water drinking causes a
biphasic change in plasma volume: initial haemoconcentration, probably
due to sympathetic acceleration, followed by haemodilution due to the
post-absorptive effect, and further suggest that the fluid shift
associated with the initial haemoconcentration is isosmotic. PMID:
11484766
(6) Int J Sports Med 1988 Apr;9(2):104-7 Blood viscosity after a
1-h submaximal exercise with and without drinking. Vandewalle H,
Lacombe C, Lelievre JC, Poirot C. Unite de Biorheologie (C.N.R.S. UA
343), Universite de Paris, France. Ten healthy subjects performed two
exercise sessions similar to an endurance training session for average
athletes (1 cycling exercise at 85% of the maximal heart rate on a
Monark cycle ergometer). In the first session, the subjects were not
allowed to drink during exercise. During the second session, the same
subjects performed the same exercise as during the first session but
they drank a beverage volume equal to the weight loss induced by the
first exercise session to verify the hypothesis that the compensation
of sweat loss by drinking could attenuate the exercise-induced blood
viscosity increase. Both protocols (with and without drinking) induced
a significant increase of hematocrit and plasma viscosity. The whole
blood viscosity increased at all shear rates but this increase was
significant only for the exercise protocol without drinking. Blood
thixotropic property, erythrocyte deformability, and erythrocyte
aggregability remained unchanged after both exercise protocols.
Hemoconcentration explained the increase of hematocrit and plasma
viscosity. Hemoconcentration was probably the consequence of a
filtration process through capillary leakage in addition to sweat
loss, which could explain the partial effect of drinking in our study.
PMID: 3384514
(7) Eur J Appl Physiol Occup Physiol 1988;57(2):220-4 Improved
thermoregulation caused by forced water intake in human desert
dwellers. Kristal-Boneh E, Glusman JG, Chaemovitz C, Cassuto Y.
Ben-Gurion University of the Negev, Beer Sheva, Israel. Residents of
the Negev desert in Israel sustain a mild state of dehydration. Low,
concentrated urine outputs, high incidence of kidney diseases and high
hematocrit ratios characterize this population. Educational programs
to increase the awareness of the population to the dangers of
dehydration have undoubtedly failed. It was our purpose to see whether
forced increased drinking will affect the above variables. Ten healthy
subjects were asked to double their normal voluntary water intake
without (phase II) and with salt supplements (50 mM NaCl, 20 mM KCl)
(phase III), for one week. After phases II and III significant
increases in body masses, decreased concentrations of serum proteins,
hemoglobin, hematocrit ratios and serum osmolalities were found. No
significant changes were found in the concentrations of sodium and
potassium in the serum. At the end of each phase, the subjects were
asked to exercise on a bicycle ergometer for 60 min at 50% VO2max in a
heated chamber at 45 degrees C, and 30%-50% relative humidity.
Experiments were terminated if and when heart-rates exceeded 180 bpm
or the rectal temperature increased to 39 degrees C. After both
experimental phases, subjects increased their tolerance to heat,
extending the exercise periods by 25% and 30%. Compared with their
starting levels, hematocrit ratios, serum proteins and hemoglobin
concentrations increased in phases II and III while no changes were
recorded in the control period (phase I). It is suggested that
spontaneous voluntary water drinking in desert dwellers is not enough
to achieve a true state of "euhydration". PMID: 3349990
(8) Diabetologia 1989 Apr;32(4):231-5 Effect on the postprandial
glycaemic level of the addition of water to a meal ingested by healthy
subjects and type 2 (non-insulin-dependent) diabetic patients.
Torsdottir I, Andersson H. Department of Clinical Nutrition,
University of Goteborg, Sahlgren's Hospital, Sweden. The effects on
postprandial glycaemic reactions of adding a glass of water to a meal
were studied in 7 healthy male subjects and 20 Type 2
(non-insulin-dependent) diabetic patients for a period of up to 3 h.
The subjects were served a meal of potatoes and meat, with or without
300 ml of water, in random order on two mornings after a 12-h fast.
The diabetic patients were considered as well-controlled or not
well-controlled according to HbA1c and blood glucose fasting values.
Water addition increased the peak blood glucose (p less than 0.02) and
serum insulin (p less than 0.02) levels in healthy subjects, and the
blood glucose concentration in well-controlled diabetic patients (p
less than 0.02). The addition of water also increased the overall
blood glucose response, calculated as the positive incremental area,
in healthy subjects by 68 +/- 25% (p less than 0.02) and in
well-controlled diabetic patients by 40 +/- 14% (p less than 0.01). In
poorly-controlled diabetic patients, however, the addition of water
did not display significant effects, probably due to the varying
fasting glycaemia in these patients. Thus, altering the physical
property of a meal by dilution with water can affect the physiological
responses; the results are considered to be relevant for the on-going
discussion concerning the use of physiological responses to foods as a
basis for diet instructions to diabetic patients. Publication Types:
Clinical Trial Randomized Controlled Trial PMID: 2759361
michaelprice
thanks for debunking the debunkers
Cheers,
Michael C Price
"Thomas Carter" <tcar...@elp.rr.com> wrote in message
news:a7b55247.02081...@posting.google.com...
David Lloyd-Jones
"michaelprice" <michae...@ntlworld.com> wrote in message
news:yFm59.18$L_2....@newsfep1-win.server.ntli.net...
> Thomas,
> thanks for debunking the debunkers
> Cheers,
> > 11-10-1998
> > DRINKING WATER PREVENTS HEART ATTACK AND STROKE
> > 30,391 healthy people with no prior history of heart disease, diabetes
> > or stroke were followed for 6 years.5 or more glasses of water per day
> > was associated with a 51% decrease in fatal heart attack, compared
> > with those who drank 2 glasses per day or less.
> > 3,809 people with a prior history of coronary heart disease, diabetes
> > or stroke were also studied for 6 years.5 or more glasses of water per
> > day was associated with a 44% decrease in the incidence of fatal
> > stroke.
> > Nonfatal heart attacks and strokes were also reduced to a somewhat
> > lesser extent.
> > This benefit was seen only with water and not with other beverages.
> > (Note: Most municipal water supplies are heavily treated with
> > chemicals and are best purified before consumption, EMC)Chan J,
> > Synnove SF. Presentation at the 20th Congress of the European Society
> > of Cardiology, Vienna, Austria, 1998. (From the Department of
> > Epidemiology, Loma Linda University Medical School, Callifornia).
> > This seems to be another slant on the same study
It's not clear to me whether this "municipal additives" angle was part of
the study, or whose responsibility it is. Still, the conclusion that one
should "purify" municipal water before drinking it does not seem to me
sound. Here in Ontario the Niagara Escarpment draws a line between
distinctly different rates of heart disease: people on the uphill side, i.e.
the Southwest of the Province, have higher rates of heart disease than those
on the downhill side, where the water has been filtered through limestone
for a zillion yeas, and hence is much harder.
People drinking "purified" water, including extremists who believe in
drinking only distilled water, are putting themselves on the uphill side,
seems to me.
Use your Culligan softener for the laundry water, not for the stuff you
drink!
-dlj.
Her Name Was Lola
"Ian Goddard" <igod...@erols.mom> wrote in message
news:3d544fe6....@news.erols.com...
> http://www.dartmouth.edu/dms/news/2002_h2/08aug2002_water.shtml
>
> Dartmouth Medical School
>
> 'Drink at least 8 glasses of water a day' -- Really?
>
> Dartmouth professor finds no scientific evidence for '8 x 8'
>
It would seem, in a "natural environment" that dogs, cats, chickens, horses,
people, etc., would drink water when they were thirsty. It therefore seems
unnatural (and what could be dangerously so) to constantly consume excessive
amounts (more than what you are thirsty for) of water. I read someplace
once where it can significantly deplete your electrolites and cause
potassium and other deficiencies. Makes sense to me.
the girl of many names
who drinks water when she is thirsty
and beer when she is not.
michaelprice
>>
>> 'Drink at least 8 glasses of water a day' -- Really?
>>
>> Dartmouth professor finds no scientific evidence for '8 x 8'
>>
>
> It would seem, in a "natural environment" that dogs, cats, chickens,
> horses, people, etc., would drink water when they were thirsty.
Perhaps not, if the risks involved (exposure to waterhole predation,
water-borne parasites, diseases) make partial dehydration a worthwhile
trade-off. Drinking whenever thirsty, for the savannah ape, may have had
considerable downside in the past, but now that water is cheap and safe
we may be underdrinking.
That the thing about evolutionary just-so stories, you can get them to say
whatever you wish.
Cheers,
Michael C Price
pbeyer
Ian Goddard wrote:
> http://www.dartmouth.edu/dms/news/2002_h2/08aug2002_water.shtml
>
> Dartmouth Medical School
>
> 'Drink at least 8 glasses of water a day' -- Really?
>
> Dartmouth professor finds no scientific evidence for '8 x 8'
>
> Hanover, NH -- It has become accepted wisdom: "Drink at least eight
> glasses of water a day!" Not necessarily, says a DMS physician Heinz
> Valtin, MD. The universal advice that has made guzzling water a
> national pastime is more urban myth than medical dogma and appears
> to lack scientific proof, he found.
>
> In an invited review published online by the American Journal of
> Physiology August 8, Valtin, 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). The review will also appear in a later issue
> of the journal.
>
> Valtin, a kidney specialist and author of two widely used textbooks
> on the kidney and water balance, sought to find the origin of this
> dictum and to examine the scientific evidence, if any, that might
> support it. He observes that we see the exhortation everywhere: from
> health writers, nutritionists, even physicians. Valtin doubts its
> validity. Indeed, he finds it, "difficult to believe that evolution
> left us with a chronic water deficit that needs to be compensated by
> forcing a high fluid intake."
>
> The 8 x 8 rule is slavishly followed. Everywhere, people carry
> bottles of water, constantly sipping from them; it is acceptable to
> drink water anywhere, anytime. A pamphlet distributed at one
> southern California university even counsels its students to "carry
> a water bottle with you. Drink often while sitting in class..."
>
> How did the obsession start? Is there any scientific evidence that
> supports the recommendation? Does the habit promote good health?
> Might it be harmful?
>
> 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.
>
> He found no scientific studies in support of 8 x 8. Rather, surveys
> of fluid intake on healthy adults of both genders, published as
> peer-reviewed documents, strongly suggest that such large amounts
> are not needed. His conclusion is supported by published studies
> showing that caffeinated drinks, such as most coffee, tea and soft
> drinks, may indeed be counted toward the daily total. He also points
> to the quantity of published experiments that attest to the
> capability of the human body for maintaining proper water balance.
>
> Valtin emphasizes that his conclusion is limited to healthy adults
> in a temperate climate leading a largely sedentary existence --
> precisely, he points out, the population and conditions that the "at
> least" in 8 x 8 refers to. At the same time, he stresses that large
> intakes of fluid, equal to and greater than 8 x 8, are advisable for
> the treatment or prevention of some diseases, such as kidney stones,
> as well as under special circumstances, such as strenuous physical
> activity, long airplane flights or hot weather. But barring those
> exceptions, he concludes that we are currently drinking enough and
> possibly even more than enough.
>
> Despite the dearth of compelling evidence, then, What's the harm?
> "The fact is that, potentially, there is harm even in water,"
> explains Valtin. Even modest increases in fluid intake can result in
> "water intoxication" if one's kidneys are unable to excrete enough
> water (urine). Such instances are not unheard of, and they have led
> to mental confusion and even death in athletes, in teenagers after
> ingesting the recreational drug Ecstasy, and in ordinary patients.
>
> And he lists other disadvantages of a high water intake: (a)
> possible exposure to pollutants, especially if sustained over many
> years; (b) frequent urination, which can be both inconvenient and
> embarrassing; (c) expense, for those who satisfy the 8 x 8
> requirements with bottled water; and (d) feelings of guilt for not
> achieving 8 x 8.
>
> Other claims discredited by scientific evidence that Valtin
> discusses include:
>
> * Thirst Is Too Late. It is often stated that by the time people
> are thirsty, they are already dehydrated. On the contrary,
> thirst begins when the concentration of blood (an accurate
> indicator of our state of hydration) has risen by less than two
> percent, whereas most experts would define dehydration as
> beginning when that concentration has risen by at least five
> percent.
>
> * Dark Urine Means Dehydration. At normal urinary volume and
> color, the concentration of the blood is within the normal
> range and nowhere near the values that are seen in meaningful
> dehydration. Therefore, the warning that dark urine reflects
> dehydration is alarmist and false in most instances.
>
> Is there scientific documentation that we do not need to drink "8 x
> 8"? There is highly suggestive evidence, says Valtin. First is the
> voluminous scientific literature on the efficacy of the
> osmoregulatory system that maintains water balance through the
> antidiuretic hormone and thirst. Second, published surveys document
> that the mean daily fluid intake of thousands of presumably healthy
> humans is less than the roughly two quarts prescribed by 8 x 8.
> Valtin argues that, in view of this evidence, the burden of proof
> that everyone needs 8 x 8 should fall on those who persist in
> advocating the high fluid intake without, apparently, citing any
> scientific support.
>
> Finally, strong evidence now indicates that not all of the
> prescribed fluid need be in the form of water. Careful peer-reviewed
> experiments have shown that caffeinated drinks should indeed count
> toward the daily fluid intake in the vast majority of persons. To a
> lesser extent, the same probably can be said for dilute alcoholic
> beverages, such as beer, if taken in moderation.
>
> "Thus, I have found no scientific proof that absolutely every person
> must 'drink at least eight glasses of water a day'," says Valtin.
> While there is some evidence that the risk of certain diseases can
> be lowered by high water intake, the quantities needed for this
> beneficial effect may be less than 8 x 8, and the recommendation can
> be limited to those particularly susceptible to the diseases in
> question.
>
> ###
>
> http://IanGoddard.net
>
> "To lengthen thy life, lessen thy meals." Benjamin Franklin
>
> Caloric Restriction: http://users.erols.com/igoddard/cr.htm
>
> I believe a good deal of the original 8x8 came from the dieting
> books-- also serves and a sort of a *cover your backside* from the
> early days of the original high protein diets-- water was also pushed
> because it gave dieters something to consume/bring some satiety/ sub
> for caloric beverages.
Pete
Eric Bohlman
>> I believe a good deal of the original 8x8 came from the dieting
>> books-- also serves and a sort of a *cover your backside* from the
>> early days of the original high protein diets-- water was also pushed
>> because it gave dieters something to consume/bring some satiety/ sub
>> for caloric beverages.
Current thinking is that water drinking doesn't really promote satiety;
water simply empties from the stomach too fast. However, foods,
especially vegetables, with a high water content *do* promote satiety
because it takes some time for the digestive system to extract the water,
so they do make you feel full for a while. The other two reasons do make
sense.
Ian Goddard
http://ajpregu.physiology.org/cgi/content/abstract/00365.2002v1
Articles in PresS, published online ahead of print August 8, 2002
Am J Physiol Regu Physiol, 10.1152/ajpregu.00365.2002
"Drink at least eight glasses of water a day" - Really?
Is there scientific evidence for "8 x 8"?
Heinz Valtin
Department of Physiology, Dartmouth Medical School, Lebanon, NH, USA
Despite the seemingly ubiquitous admonition to "drink at least eight
8-ounce glasses of water a day" (with an accompanying reminder that
beverages containing caffeine and alcohol do not count),rigorous proof
for this counsel appears to be lacking. This review sought to find the
origin of this advice (called "8 x 8" for short) and to examine the
scientific evidence, if any, that might support it. The search
included not only electronic modes but also a cursory examination of
the older literature that is not covered in electronic databases - and
most importantly and fruitfully, extensive consultation with several
nutritionists who specialize in the field of thirst and drinking
fluids. No scientific studies were found in support of 8 x 8. Rather,
surveys of food and fluid intake on thousands of adults of both
genders - analyses of which have been published in peer-reviewed
journals - strongly suggest that such large amounts are not needed
because the surveyed persons were presumably healthy and certainly not
overtly ill. This conclusion is supported by published studies showing
that caffeinated drinks (and, to a lesser extent, alcoholic beverages)
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. It is to be emphasized that the conclusion is limited to
healthy adults in a temperate climate leading a largely sedentary
existence - precisely, however, the population and conditions that
the "at least" in 8 x 8 refers to. Equally to be emphasized - lest
the message of this review be misconstrued - is the fact (based on
published evidence) that large intakes of fluid, equal to and greater
than 8 x 8, are advisable for the treatment or prevention of some
diseases, and certainly are called for under special circumstances,
such as vigorous work and exercise, especially in hot climates. Since
it is difficult or impossible to prove a negative - in this instance,
the absence of scientific literature supporting the 8 x 8
recommendation - the author invites communications from readers who
are aware of pertinent publications.
To whom correspondence should be addressed. E-mail:
heinz....@dartmouth.edu.
Ian Goddard
To: Heinz Valtin <***>
From: Ian Goddard <***>
Subject: Ambiguity in Your Review?
Hello Dr Valtin,
This statement you make is difficult to understand:
"Equally to be emphasized - lest the message of this review be
misconstrued - is the fact (based on published evidence) that
large intakes of fluid, equal to and greater than 8 x 8, are
advisable for the treatment or prevention of some diseases,
and certainly are called for under special circumstances, such
as vigorous work and exercise, especially in hot climates."
http://ajpregu.physiology.org/cgi/content/abstract/00365.2002v1
You appear to state that evidence indicates that healthy
people can prevent some diseases (since those in whom a
disease may be prevented are currently healthy) if they
drink fluid equal to or greater than 8 x 8. Well, is that
not essentially what the 8 X 8 recommendation implies, ie,
that such drinking will maintain health by preventing some
illnesses? I hope you can clarify this apparent ambiguity.
Thank you for your attention.
-- Ian Goddard
michaelprice
Heinz Valtin. Be interesting to see what he has to say. Will report back.
Cheers,
Michael C Price
Dear Heinz Valtin
re: "Drink at least eight glasses of water a day" - Really?
Is there scientific evidence for "8 x 8"?
I would be interested to hear your comments on the study below:
Am J Epidemiol 2002 May 1;155(9):827-33
Water, other fluids, and fatal coronary heart disease: the Adventist Health
Study.
Chan J, Knutsen SF, Blix GG, Lee JW, Fraser GE.
Adventist Health Studies, School of Public Health, Loma Linda University,
Loma Linda, CA 92350, USA. jc...@sph.llu.edu
Whole blood viscosity, plasma viscosity, hematocrit, and fibrinogen are
considered independent risk factors for coronary heart disease and can be
elevated by dehydration. The associations between fatal coronary heart
disease and intake of water and fluids other than water were examined among
the 8,280 male and 12,017 female participants aged 38-100 years who were
without heart disease, stroke, or diabetes at baseline in 1976 in the
Adventist Health Study, a prospective cohort study. A total of 246 fatal
coronary heart disease events occurred during the 6-year follow-up. High
daily intakes of water (five or more glasses) compared with low (two or
fewer glasses) were associated with a relative risk in men of 0.46 (95%
confidence interval (CI): 0.28, 0.75; p trend = 0.001) and, in women, of
0.59 (95% CI: 0.36, 0.97). A high versus low intake of fluids other than
water was associated with a relative risk of 2.47 (95% CI: 1.04, 5.88) in
women and of 1.46 (95% CI: 0.7, 3.03) in men. All associations remained
virtually unchanged in multivariate analysis adjusting for age, smoking,
hypertension, body mass index, education, and (in women only) hormone
replacement therapy. Fluid intake as a putative coronary heart disease risk
factor may deserve further consideration in other populations or using other
study designs.
PMID: 11978586
Cheers,
Michael C Price
michaelprice
> People drinking "purified" water, including extremists who believe in
> drinking only distilled water, are putting themselves on the uphill side,
> seems to me.
>
> Use your Culligan softener for the laundry water, not for the stuff you
> drink!
I agree and here's a study to back it up:
Eur Heart J 1992 Jun;13(6):721-7
Cardiovascular mortality and morbidity in seven counties in Sweden in
relation to water hardness and geological settings. The project: myocardial
infarction in mid-Sweden.
Nerbrand C, Svardsudd K, Ek J, Tibblin G.
Uppsala University, Department of Family Medicine, Sweden.
An east-west regional gradient in cardiovascular mortality was found within
seven counties in mid-Sweden during the years 1969-1983. The mortality
differences were of considerable magnitude for ischaemic heart disease (IHD)
as well as for stroke. In previous reports, in which the distribution of
risk factors among middle-aged men was presented, the moderate variation
among the communities could not explain the mortality variation. Water
hardness has previously been reported to be inversely related to
cardiovascular mortality in several countries. In this paper, water samples
from all 76 communities in seven counties were analysed in relation to
mortality rates from IHD and stroke for men and women. Water hardness (Ca+Mg
and other minor constituents), and the sulphate and bicarbonate
concentrations of the drinking water were inversely related to IHD as well
as stroke mortality. The water factors were also inversely related to
non-fatal IHD even when account was taken of the age variation and the
traditional risk factors as measured by a postal questionnaire. Variation of
the water factors accounted for 41% of the variation in IHD mortality rate
and 14% of the variation in stroke mortality rate over the 76 communities.
PMID: 1623858
BTW, it was Thomas and "mike" who posted the impressive
pro-water studies not me. Great work Thomas and Mike!
Cheers,
Michael C Price
michaelprice
I think Heinz Valtin's mistake is contained in :
"Rather, surveys of food and fluid intake on thousands of adults
of both genders - analyses of which have been published in
peer-reviewed journals - strongly suggest that such large amounts
are not needed because the surveyed persons were presumably
^^^^^^^^^
healthy and certainly not overtly ill."
which is the same mistake as the anti-megadosing folks make, of
assuming the average, non-overtly ill person is optimally healthy.
Still, it'll be interesting to see what he says. Until then, glug, glug
Cheers,
Michael C Price
"Ian Goddard" <igod...@erols.mom> wrote in message
news:3d58395a....@news.erols.com...
drfrank21
Good point(s) that you make. I wonder tho' if he was just trying to
cover himself with that statement. But I think he's differentiating
from treating
special circumstances (ie acute dehydration ) from the water "gurus"
theory of chronic dehydration causing numerous types of diseases.
As a water imbiber myself, the human body has fairly tolerant levels
beween severe dehydration and excessive hydration (leading to water
poisoning). So the question becomes that although 8x8 is harmless
how much good does it do ya.
frank
michaelprice
do I gather that you never received a response from Dr Valtin?
Neither did I.
Cheers,
Michael C Price
"Ian Goddard" <igod...@erols.mom> wrote in message
news:3d58395a....@news.erols.com...
Ian Goddard
>Ian,
>do I gather that you never received a response from Dr Valtin?
>Neither did I.
>Cheers,
>Michael C Price
IAN: No reply here. Valtin's abstract appears to be ambiguous,
saying "no scientific studies were found in support of 8 x 8,"
and that "based on published evidence ... large intakes of fluid,
equal to and greater than 8 x 8, are advisable for the treatment
or prevention of some diseases." He also seems to define healthy
people as "not overtly ill." So Valtin appears to say there's no
evidence that 8 x 8 is necessary to maintain health but there is
evidence that 8 x 8 is necessary to prevent some diseases. In my
book preventing some diseases is the same as maintaining health.
http://groups.google.com/groups?selm=3d58395a.157559000%40news.erols.com
http://ajpregu.physiology.org/cgi/content/abstract/00365.2002v1
"To lengthen thy life, lessen thy meals." Benjamin Franklin
Caloric Restriction: http://users.erols.com/igoddard/cr.htm
Ongoing CR-monkey-study update: "In the monkeys...those on
reduced feeding since the study started are dying at a rate
that is about half that of the monkeys receiving a full food
ration." Associated Press: Eating less may extend human life.
August 1, 2002 : http://www.msnbc.com/news/788746.asp?0si=-
peter_mann
search on google and found this site: http://www.no-salt.com/
I'm wondering if anyone had any experience with a no-salt system.
Thanks.
Peter
"Ian Goddard" <igod...@erols.mom> wrote in message
news:q21vmus5oorr3ps8o...@4ax.com...
michaelprice
> Ian,
> do I gather that you never received a response from Dr Valtin?
> Neither did I.
> Cheers,
> Michael C Price
I recently recived a most informative reply from Dr Valtin.
I sent a response and, not hearing back (he is busy), am posting
it here:
*********************
Dear Heinz Valtin,
thanks for your informative reply. Your interview was reported in
several internet newsgroups and set off a vigorous debate, as I'm
sure you can imagine.
http://groups.google.com/groups?q=%22Water-Drinking+Myth%22+AND+valtin&hl=en
&lr=&ie=UTF-8&safe=off&selm=3d544fe6.351868923%40news.erols.com&rnum=1
If the above URL gets mangled a googlegroups search for "Water-Drinking
Myth?" and your name should be sufficient to locate it. :-) Do you have
any objections to me forwarding your helpful and informative response to
the various discussion groups?
Thanks for the pointer to the review. In it you say:
"......it is hard to imagine that evolutionary development left us with a
chronic water deficit that has to be compensated by forcing fluid intake."
I find it quite easy to imagine such a situation. Of course imagining
something is possible is far short of proof or even plausibility,
nevertheless
consider this:
For our savannah ancestors paying a visit to the watering hole was an
expensive, time-consuming and risky activity due to exposure to waterhole
predation, water-borne parasites and diseases; under these circumstances
partial dehydration is a worthwhile trade-off. As a result our thirst
mechanism
is not adjusted, in the evolutionary sense, to the availability of clean,
cheap
water in the modern world. Hence, drinking more water than we naturally
feel inclined to may be beneficial to our health.
And this is what we find in hot, arid climates, namely that forced water
intake improves health by some physiological measures[1]. Your study
specifically excludes non-temperate environments, so this isn't a criticism
of your work, but surely if the thirst mechanism is non-optimal in arid
conditions
it would be unwise to assume it functions optimally in more temperate
climes?
[1] Improved thermoregulation caused by forced water intake in human desert
dwellers by Kristal-Boneh E, Glusman JG, Chaemovitz C, Cassuto Y in Eur J
Appl Physiol Occup Physiol 1988;57(2):220-4
Ben-Gurion University of the Negev, Beer Sheva, Israel.
Residents of the Negev desert in Israel sustain a mild state of dehydration.
Low, concentrated urine outputs, high incidence of kidney diseases and high
hematocrit ratios characterize this population. Educational programs to
increase the awareness of the population to the dangers of dehydration have
undoubtedly failed. It was our purpose to see whether forced increased
drinking will affect the above variables. Ten healthy subjects were asked to
double their normal voluntary water intake without (phase II) and with salt
supplements (50 mM NaCl, 20 mM KCl) (phase III), for one week. After phases
II and III significant increases in body masses, decreased concentrations of
serum proteins, hemoglobin, hematocrit ratios and serum osmolalities were
found. No significant changes were found in the concentrations of sodium and
potassium in the serum. At the end of each phase, the subjects were asked to
exercise on a bicycle ergometer for 60 min at 50% VO2max in a heated chamber
at 45 degrees C, and 30%-50% relative humidity. Experiments were terminated
if and when heart-rates exceeded 180 bpm or the rectal temperature increased
to 39 degrees C. After both experimental phases, subjects increased their
tolerance to heat, extending the exercise periods by 25% and 30%. Compared
with their starting levels, hematocrit ratios, serum proteins and hemoglobin
concentrations increased in phases II and III while no changes were recorded
in the control period (phase I). It is suggested that spontaneous voluntary
water drinking in desert dwellers is not enough to achieve a true state of
"euhydration".
PMID: 3349990
My interest is merely as an interested consumer, I have no
biological/medical
qualifications. Nor do I work for a water company!
Cheers,
Michael
----- Original Message -----
From: "Heinz Valtin" <Heinz....@Dartmouth.EDU>
To: <michae...@ntlworld.com>
Sent: Tuesday, September 03, 2002 6:15 PM
Subject: Re: "Drink at least eight glasses of water a day" - Really?
September 3, 2002
Dear Michael Price:
Please accept my apologies for taking so long to answer your thoughtful
note. Ever since my article appeared on August 8, I have been inundated
with mail and requests for interviews -- the latter from four continents,
literally.
Fortunately, I had spotted the article by Dr. Chan and her associates before
I submitted my article for publication. Here is what I wrote about their
study:
"Chan and her associates (21) have carefully analyzed the possible
association between water intake and fatal coronary heart disease in 12,017
women and 8,280 men who participated in the prospective Adventist Health
Study. They found, at a 6-year follow-up point, that women who drank five
or more glasses of water per day (1,185 mL or more) reduced their risk of
fatal coronary heart disease by approximately 41% when compared to women
who drank two glasses or less (474 mL or less). The comparable figure in
men was 54% less risk. The effect was limited to water; in fact, the
drinking
of "fluids other than water" (coffee, tea, juices, soft drinks) appeared to
increase the risk of fatal coronary heart disease.
"In their very cautious analysis of these findings, the authors (21)
point out: (a) that the correlations are not necessarily causal (although
they may involve the effect of hydration on hemorheological variables such
as blood viscosity); (b) that the findings might be unique to Seventh Day
Adventists living in California, especially since they drink considerably
more water and less caffeinated and alcoholic drinks than do other groups;
(c) that the trends in the risks are significant only in men, whereas in
women the risk of fatal coronary heart disease was as low as or lower in
those drinking 3 to 4 glasses of water a day (711 to 948 mL) as in those who
drank 5 or more glasses; and (d) that other studies, likely ones with
experimental design, will be needed to confirm the findings. In the context
of this article, I would point out, further, that the reference point of 2
glasses of water per day or less (474 mL or less) is considerably lower than
what most people drink (see Table 2), and that 3 to 4 glasses a day, and
certainly 5 glasses a day, may suffice to lower the risk."
I checked out the wording with Dr. Chan before my article was published, and
she said that I quote the material accurately. You can see from my tone
that I consider hers to be precisely the kind of careful scientific studis
that are needed to ascertain the possible benefits of water intake. By and
large, the studies I have seen on this question, and have cited in my
article, suggest that there is not yet full agreement and that, often, fluid
intake of less than eight glasses per day will elicit the beneficial
effects.
If you would like to see my full article, you can find it at the following
URL:
<http://www.dartmouth.edu/dms/news/2002_h2/08aug2002_water.shtml>
Then go to "Read the invited review.pdf".
I would be interested to learn where you are located and what work you do.
Thanks very much for writing.
Best wishes, Heinz Valtin, M.D.
==========================================================
--- You wrote on 8/11/02:
PMID: 11978586
Cheers,
Michael C Price
ada
--
Cheers,
Michael C Price
Ian Goddard
>I recently recived a most informative reply from Dr Valtin.
>I sent a response and, not hearing back (he is busy), am posting
>it here:
IAN: Thanks Mike. I also recently got a reply from
Valtin. Based on the studies in his review finding a
correlation between higher water intake and reduced
risk of diseases such as cancer and heart disease,
I'll be sure to drink at least 5 cups of water a day.
The fact that there is not "proof" that eight glasses
a day is necessary dose not speak to the *evidence*
that higher water intake *may* prevent some diseases.
Unfortunately the reports on Valtin's review make the
error of believing that "no proof" = "no evidence."