http://yarchive.net/med/osmotic_damage.htmlFrom: ((Steven B. Harris))
Subject: Re: How much H2O a day?
Date: 11 Jul 1995
Newsgroups: misc.health.alternative
In <3tscha$7k8@mordred.gatech.edu> garland@aql.aql.gatech.edu (Leslie
Garland) writes:
>Every year one or more people die from drinking ONLY distilled water
>(often high school students who have just learned about distilled water
>and think since it is pure water, it must be the best water). Your body
>needs electrolytes to function;
Yep, and you get all you need from your food. Food is a far more
important source of every electrolyte than water. The only
major electrolyte which water ever helps supplement much is magnesium,
and even here food is by far the most important contributer.
> when considerable amounts of distilled
>water are consumed, your cells lyce (sp?) i.e. explode.
Nonsense. This happens to porous red blood cells if you put them in
distilled water, but not the very well structurally-reinforced and
non-porous cells lining your mucous membranes and GI tract. In any
case, the difference in osmotic load between distilled water and many
tapwaters is trivial. Body osmolality is about 280 milliosmols, and
your average springwater might run 20 or 30. The difference between
there and zero, so far as you cells care, is nothing. Blood cells lyse
just as well in tapwater-- I've done this experiment for myself.
> This is due to
>the fact that the electrolyte concentration outside the cell is not close
>to that inside the cell. Your body tries to correct this imbalance and
>due to the nature of osmosis in cell membranes, the electrolytes can't
>get out of the cell, so it tries to dilute the concentration inside the
>cell by adding water. It will continue to add water until the membrane
>bursts.
Again, somebody showed you this for RBCs, and now you think it's the way
there rest of the body opperates. It isn't. Gut epithelial cells
actually have very few channels for water to enter along the osmotic
gradient. Most water you drink enters your bloodsteam not though cells,
but through pores in in the tight junctions between epithelial cells.
And the rate of this is strictly controlled by the number of pores, not
by the osmolality difference. Even with a max osm difference between
what you drink and your blood, the influx of pure water from gut to
blood is not fast enough to hemolyze your blood.
> If enough cells disintigrate, death will result. (see any
>physical chemistry text on osmosis or basic biochem texts)
Indeed, see Guyton, which will tell you how the entire process works.
No text will tell you that drinking distilled water is harmful, unless
of course you drink gallons and eat no salt. But even beer without
pretzels can cause hyponatremia if you do that. Or hard tapwater, which
is also low in sodium, drunk in large quantities without any food.
>When I was in college, one of our TA's died this way.
I doubt it. If he died of water intoxication, it wasn't due to
distilled water per se. It was due to too much water, and too little
food/salt.
>>BTW, coffee, tea, and other caffeinated beverages (ie: coke, mountain
>>dew, pepsi...) do not rehydrate the body at all. In fact, they do the
>>opposite. Caffeine is a diuretic, as is alcohol.
It's a diuretic, but not enough to completely make up for the water
content. If you were out in the desert and had nothing but cold coffee,
you'd be well advised to drink it. Same with beer. With wine, and
certainly with distilled spirits, you would indeed probably be worse
off.
>>Alcohol, in addition to being a diuretic, also undergoes a chemical
reaction with water to form esters, which further dehydrates you<<
Sorry, but I need to see a chemical reaction diagram for that. Esters
are formed from alcohols and organic acids, not alcohol and water.
> (that's why people
>with hangovers have dry mouth).
Nah, they have dry mouth due to the simple dehydration from drinking
things that are too high in alcohol content. Beer hangovers are not
nearly so bad in this regard as those from other alcoholic drinks.
Steve Harris, M.D.
(Yes, my undergrad degree is in chemistry)
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