From: ((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) From: ((Steven B. Harris)) Subject: Re: How much H2O a day? Date: 12 Jul 1995 Newsgroups: misc.health.alternative In <DBJ6BB.BxK@spdcc.com> dyer@spdcc.com (Steve Dyer) writes: (Quoting another correspondant:) > >Your body > >needs electrolytes to function; when considerable amounts of distilled > >water are consumed, your cells lyce (sp?) i.e. explode. 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. If enough cells disintigrate, death will result. (see any > >physical chemistry text on osmosis or basic biochem texts) Dyer: >The osmotic difference between distilled water and tap or spring water >is physiologically insignificant. No one gets their electrolytes from >the water they drink, anyway! Correct. With the possible exception of some supplemental magnesium. I have explained in a private letter to this writer that her theory predicts that if you pour distilled water over the corneas or the tongue or the inside of the cheek, that after a bit of being bathed in a stream of this pure water the cells will osmotically explode and your mucosal tissue will slough away to reveal a raw burned under-layer, which will itself osmotically lyse, and so on. Nasty. But since nothing of the kind happens (and yes, kids, Doc Harris says you CAN try this experiment at home!), then some theories need rethinking. Steve Harris, M.D. P.S. If you pour distilled water into an open wound it DOES hurt, although it's not exactly osmotic "acid". The pain is indeed from osmotic damage, since saline is not nearly so painful. But this just illustrates the osmotic toughness of the mucous membranes, such as line the gut. Also, it demonstrates that even exposed tissue is osmotically much tougher than RBCs. You can pour distilled water in a wound all you want, and you won't do that much damage. S. From: Steve Harris <sbharris@ix.netcom.com> Newsgroups: sci.med.nutrition Subject: Re: Sugar & Salt Date: 22 Jul 2005 20:17:47 -0700 Message-ID: <1122088667.626824.3040@z14g2000cwz.googlegroups.com> montygram wrote: > But what about the OP's question. Saying "osmosis" is not going to > help most people who read posts here. If you can't explain why > bacteria or fungus have difficulty with granulated sugar, why bother to > post here? Just talk terms of art with your science buddies. COMMENT: If the OP already understands "osmosis" then you can say a lot of time by simply referring him to the word. This happens. The first time I saw granulated sugar troweled into a non-union osteomyelotic thoracotomy wound infected with MRSA, I couldn't believe it. "How the the hell is THAT going to work?" said I. "Osmotic shock as antibiotic." Ah, so. Here's the short version. All growing cells live in little pools of water. All cells have pretty dilute watery contents, because you need a lot of water to let stuff move around, and also the non-water contents are pretty big molecules that don't count much as solvents because they take up a lot of space. The number of impacts against a wall they make, which compete with water molecules trying to get in or out, is negligable. All cells are surrounded by soap-like membranes which have to pass water inward, so the cell can drink. The membranes themselves can't dissolve in water or the cell woudl fall apart. Therefore it must be made of something waxy that water can't just move into and disolve into. Therefore it has have physical little holes in it so the water can pass. These can be little passive holes that pass water both ways without much interference, or the "hole" can be a crevice in a protein acting like a pump (think of a water wheel). In the case lf the passive hole, it works fine if the concentration of water outside the cell is lower than inside, which causes water to just diffuse in, along the gradient. This happens because water molecules impact the hole more outside than inside, so more of them go that way (out to in). If there's a protein pump like the water wheel, which must shuttle water inward against a concentration gradient (low concentration outside to high inside) it has to do work. But there's a limit to how much work these things can do uphill. No pump is perfect, and if the gradient is too great it, acts like a pressure, adn the leaks in the "wrong direction," like leaks in an old submarine or boat, can quickly swamp the bilge pumps or whatever. Really high sugar and salt concentrations outside cells present VERY low water concentations in solutions. And HUGE gradients in water concentration. It's practically impossible for the cell to get usable water out of them, because water leaks out passively faster than it can be pumped in. Think of seawater, but much worse. Cells eithe have to close down completely and go into suspended animation, or else prune up and die. SBH From: Steve Harris <sbharris@ix.netcom.com> Subject: Sugar & Salt Newsgroups: sci.med.nutrition Date: 22 Jul 2005 08:01:16 GMT Message-ID: <42e0a7cc$0$17744$6cceaf45@news.echoforum.com> rudy-canoza@excite.com wrote: > IanW wrote: > > Why doesn't sugar and salt go off? ie: not get polluted by microorganisms? > > > > Bigus > > > No protein present in either one. COMMENT: But honey doesn't decay or ferment either, and it certainly has enough protein to provide some nutrition for microbes (not to mention bee larvae). The main reason for the self preservation of sugar is the osmotic one explained. If you dilute honey with water so the osmotic forces are low enough, it WILL ferment. Then you get mead. Indeed, if you make even dilute sugar water with that horrible supposedly nutrition-free "white refined table sugar," it will grow all kinds of interesting microbes as well. It is not, of course, quite pure. And the difference is everything. SBH |
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