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Claim: Drinking distilled water can actually remove needed minerals from the body, due the lack of minerals in the water, and therefore do damage to the body.

I have a hard time accepting this due to amount of minerals that can be found in the body. However, I know that you can drown the body by drinking to much water and that body does use water to remove waste from it cells.

Mad Scientist
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Scott
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    Welcome to Skeptics! We want to focus our attention on doubtful claims that are widely held or are made by notable people. Please [provide some references](http://meta.skeptics.stackexchange.com/questions/882/what-are-the-attributes-of-a-good-question/883#883) to places where this claim is being made. – Oddthinking Jul 29 '11 at 15:46
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    @Odd I've heard this claim quite a few times now, in variants from just being unhealthy to being lethal. – Mad Scientist Jul 29 '11 at 17:05
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    @Fabian, I've heard pseudo-science claims that the [water you drink must be pure](http://www.evolutionhealth.com/bragg_h20.html), but I had never heard claims it must be impure! – Oddthinking Jul 29 '11 at 18:17
  • @Odd, I've just heard it through different conversations with nutritionist. I unaware of any physical or notable source. – Scott Jul 29 '11 at 18:43
  • I have heard anecdotally about athletes using distilled water to DEHYDRATE themselves (in order to lose weight to make specified weight limits for boxing/wrestling/judo/etc). Supposedly, the distilled water somehow forces more water out through your urine/sweat than is put in via drinking it, kinda like how celery is calorie-negative when you eat it. – Graham Oct 14 '15 at 20:19
  • Anecdotal also, but Richelieu used to lock his opponents and gave them nothing but "purified water" and flat, unsalted bread. The story goes saying that those people got crazy fairly quickly and that some even started drinking their own blood. – MakorDal Jul 12 '16 at 06:52
  • And drinking distilled water with limited other mineral sources can make one dizzy and disorientated ( ie. drunk) from electrolyte imbalance. An acquaintance ( PHD chemist) did this on a bet many years ago. – blacksmith37 Oct 28 '17 at 22:01
  • There must be few other question on this site that have so many comments uncritically using implausible anecdotes to reinforce the credibility of the claim. – matt_black Jan 17 '20 at 20:55

3 Answers3

24

This is true.

I did some digging: the Wikipedia article on water purification linked to a study by the WHO that discusses the risks of drinking demineralised water.

It states

It has been adequately demonstrated that consuming water of low mineral content has a negative effect on homeostasis mechanisms, compromising the mineral and water metabolism in the body

This means that it interferes with the body's attempts to keep the pH and mineral composition of internal organs constant, which is a more exact way of saying that it removes minerals from your body.

It reports some of the effects:

Results of experiments in human volunteers evaluated by researchers for the WHO report are in agreement with those in animal experiments and suggest the basic mechanism of the effects of water low in TDS (e.g. < 100 mg/L) on water and mineral homeostasis. Low-mineral water markedly: 1.) increased diuresis (almost by 20%, on average), body water volume, and serum sodium concentrations, 2.) decreased serum potassium concentration, and 3.) increased the elimination of sodium, potassium, chloride, calcium and magnesium ions from the body.

The report warns of other indirect downsides of demineralised water, including corrosion of pipes, and reduction of minerals from food cooked with it.

Ref: Health Risks From Drinking Demineralised Water, Frantisek Kozisek, Water safety plan manual: Step-by-step risk management for drinking-water suppliers, 2009, Chapter 12.

Oddthinking
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devtesla
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    To me this seems fairly intuitive. Distilled water has nothing but water and your body moves things around using (among other things) osmosis. Since osmosis tends towards equilibrium, adding some nothing to your body would tend to drain whatever you previously had. But regarding hyponatremic shock, it can happen with any [water that doesn't have the required salts or electrolytes normally found in your body](https://secure.wikimedia.org/wikipedia/en/wiki/Water_intoxication). – Mr. Shiny and New 安宇 Jul 29 '11 at 17:28
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    I disagree. This didn't strike me as intuitive at all. I was surprised by the result. Note: if we are merely talking about replacing the litre or so of water drunk per day with demineralized water and maintaining a healthy diet which includes plenty of minerals in your food, much (not all!) of the evidence in the WHO paper and all of the hyponatremic shock info is irrelevant. – Oddthinking Jul 29 '11 at 18:00
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    @Oddthinking: If you're saying "Take a normal diet and replace whatever water is consumed with distilled water", then you are probably right in that it is a minor reduction in minerals. If, however, you add a significant quantity of distilled water, it seems obvious to me that it would upset the balance to a greater degree than normal water. – Mr. Shiny and New 安宇 Jul 29 '11 at 18:16
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    @Mr.ShinyandNew: Okay. Sounds like we agree. And that if you drink 4+ litres of any sort of water in a short period, you are risking hyponatremic shock. (LD50 for water seems to be about 90-190 mL/kg, but I haven't found a reliable source.) – Oddthinking Jul 29 '11 at 18:34
  • @OT: even if the effects are small when drinking small amounts, they're there nevertheless. And do mind that (re your snide remark to the question) that there's a difference between dirty water and water. Just regular tap or mineral water isn't dirty (in most places) and quite a world apart from distilled water in mineral content. – jwenting Aug 15 '11 at 07:33
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    -1; this doesn't make physical sense. The difference in osmotic shock between the ~1 mM concentration of stuff in "normal" water and ~0 mM in distilled water is negligible; rainwater is used in many places and has no appreciable ionic content; the rest of the water doesn't know whether the ions are present, so claims of toxicity and "aggressiveness" are silly; one can gain equivalent salts by eating a couple of potato chips per liter; etc. etc.. No fault of yours, devtesla, but this answer needs _much_ better evidence; I can't in good conscience not downvote something almost surely wrong. – Rex Kerr Oct 06 '11 at 05:51
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    @Rex, we have one commenter saying "fairly intuitive" and another saying "almost surely wrong". Excellent! This is when I learn something new! I look forward to seeing an answer from you with some evidence to counter devtesla's. – Oddthinking Oct 06 '11 at 06:13
  • @Oddthinking - I'm not sure I have time. If I'd had time, I would have just posted a different answer. Maybe later.... – Rex Kerr Oct 06 '11 at 06:36
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    @Rex, Sure, I look forward to it. In the mean time, as a good little skeptic, I have to provisionally accept the answer that cites empirical evidence, even though it contradicts my original guess on the matter. – Oddthinking Oct 06 '11 at 11:58
  • The minerals would actually be removed by the kidneys not the drinking water. The water may draw minerals and chemicals into the digestive process but I find it difficult to believe that consuming pure water would have any signifgant negative health effect. – Chad Oct 06 '11 at 13:43
  • @Oddthinking - Finally got around to adding my own answer. – Rex Kerr Nov 06 '11 at 20:12
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    The trouble with this question and this answer is that they don't properly address "compared to what". Distilled water is *more corrosive*. Distilled water *drains the body* but **compared to what.** Compared to sea water, I'm sure distilled water isn't that corrosive, nor is it less likely to upset your ionic balance. There are minor and mostly trivial differences between distilled, soft and hard water. but this differences don't justify the sort of language used here. – matt_black Nov 06 '11 at 21:56
  • The same Wiki article quotes "Manufacturers of home water distillers claim the opposite—that minerals in water are the cause of many diseases, and that most beneficial minerals come from food, not water.[29][30] They quote the American Medical Association as saying "The body's need for minerals is largely met through foods, not drinking water." he WHO report agrees that "drinking water, with some rare exceptions, is not the major source of essential elements for humans" and is "not the major source of our calcium and magnesium intake", yet states that demineralized water is harmful anyway." – neydroydrec Nov 03 '12 at 09:38
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    It can be especially dangerous if you are sweating a lot and drinking a lot in turn. You could have a cardiac arrest. Nearly happened to a friend of mine with regular water. Paramedics in hot climates are usually aware of this. –  Jul 13 '16 at 08:29
  • A bit silly. If you do not eat or drink anything with the necessary minerals in it then obviously you will eventually suffer from mineral depletion. But likely about 4 oz of orange juice a day would supply all the minerals that would be present in the mythical 8 glasses of distilled water. – Daniel R Hicks Oct 26 '17 at 23:42
  • The "corrosion of pipes" concern may refer to lead piping: if you have lead piping and hard water, a PbCO3 scaling forms that (as long as it is not disturbed) very much reduces the amount of lead leaking into the transported water. With soft water (and demineralized being an extreme of soft) no such protective scaling can form, and lead will constantly be dissolved. – cbeleites unhappy with SX Oct 28 '17 at 19:13
  • There is a great deal of confusion here between a paper that summarises other work (the source is a review) and actually good primary sources. Many of the wildest claims come from what look line dodgy sources where we can't check the methods used. Some claims (like the major one that distilled water is corrosive) are *not referenced at all* and sound like a schoolboy misunderstanding of how chemists handle and use distilled water. Given this, arguments that say "this result appears in a published paper therefore it must be right" should be dismissed with extreme prejudice. – matt_black Jan 17 '20 at 20:36
  • @matt_black the issue they are referring to with distilled water is that there will be dissolved oxygen in the water. Since there are no salts in the water, that oxygen will tend to bond more easily to piping materials (such as iron, various plastics, etc) than it would if the water contained a normal level of dissolved solids – thelawnet Nov 11 '21 at 09:23
  • @thelawnet There will be dissolved oxygen in **all** water. How is that different with distilled water in *any way*? Again, the science in this paper is garbage and that main claim is not referenced at all. – matt_black Nov 11 '21 at 09:36
  • I continue to be appalled by the degree f credibility granted to the source for this answer. It is absolutely awful as a review with simply no critical judgement about the quality of the sources it uses and with many strong claims not based on any sources. It looks to me as though many credulous skeptics have gone down the road of "it has been published, therefore it is reliable" (possibly without reading the actual source. This is extremely disturbing and unskeptical. – matt_black Nov 11 '21 at 09:48
  • @matt_black of course, but that's not what I said. I haven't checked the study's claims on health issues, I'm just pointing out that the issues with distilled water in relation to corrosion specifically are verifiable widely reported e.g. https://www.researchgate.net/publication/261133505_Corrosion_Of_Carbon_Steel_In_Waters_Of_Varying_Purity_And_Velocity Rabald et al reported on the corrosion rates of steel in flowing tap water and in distilled water. In flowing tap water, they found that steel corroded at 0.25 mm/yr. However in distilled water, it corroded at 73 mm/yr (about 300x faster). – thelawnet Nov 11 '21 at 10:03
  • @thelawnet The abstract of the link says the opposite. *Initial* corrosion rates were high with purified water but rapidly fell to low levels. Plus *adding* minerals back to the water made corrosion worse. – matt_black Nov 11 '21 at 10:07
  • @matt_black We were discussing *distilled* water. That study is not about distilled water, however it references an earlier study about distilled water, which is not online. The reason for the falling to low levels is that the piping passivates (is covered with rust) when a sufficient water velocity is achieved, which reduces the corrosion. They specifically encouraged corrosion by adding corrosion-promoting sodium chloride. This is not just generic 'minerals'. If they had added water hardness, i.e. Mg or Ca, this would precipitate on the pipe instead, *reducing* corrosion.They did not do this – thelawnet Nov 11 '21 at 10:24
  • @thelawnet You quoted the paper claiming it showed something it didn't. Passivation happened with purified water (and isn't "rust": steel forms a thin oxide film like aluminium) which suggests corrosion is not an issue. Now you want validation from another paper we can't check? – matt_black Nov 11 '21 at 10:31
  • @matt_black Steel pipe that is exposed to distilled water will corrode. My initial reference was clear, it says 'Rabald et al reported', with the sourc eof that. I'm not sure why you are being obstreperous. Here is another study: https://bit.ly/3qsZIFN Soft water containing no chloride and little hardness had MUCH higher corrosion under all conditions (flowing and static) than hard water also containing some chloride, however the chloride specifically causes pitting whereas the soft (or distilled!) water has uniform corrosion. – thelawnet Nov 11 '21 at 11:11
  • @thelawnet That article is about **soft** water not distilled water. Most soft water is acidic and contains things that do promote corrosion that are not present in distilled water. I'm being obstreperous as the references you quote repeatedly fail to demonstrate what you claim (the same problem with the original answer.) – matt_black Nov 12 '21 at 00:28
24

This is not true, not in any meaningful sense.

First of all, non-distilled water has extremely widely varying levels of various minerals; for example among U.S. cities magnesium concentration varies by 300-fold (and other minerals also vary widely). Since leeching is proportional to concentration difference, the difference between zero and a tiny trace is much less chemically significant than the difference between a tiny trace and a 300-fold larger trace.

Second of all, the minerals in drinking water are, for a balanced diet, overwhelmed by the minerals present in food. For example, in the U.S. cities list, if you drink 2L of water of the highest mineral concentration, you would get 120, 180, 220, and 30 mg of magnesium, calcium, sodium, and potassium, respectively. The daily recommended intake (linked from here) for 19-30 year old males is 400, 1000, 1500, and 4700 mg. These differences are vast, and are similarly large for the other minerals I've checked. Certainly, since water has no memory, drinking distilled water wouldn't take away more than 120 mg of magnesium beyond what drinking the highest magnesium concentration tap water in the U.S., and this is a negligible amount compared to the daily intake.

However, if one has poor nutrition to begin with, water may provide (no guarantees, given the large variations!) enough of some mineral to alleviate negative impacts on health. Still, that distilled water is "removing minerals" is not a useful way to think about it. Yes, of course when we excrete waste products, some minerals go along; if you're short of some mineral, you'll then be even shorter. If you're lucky enough to have the deficiency covered by the water you drink, then you'll of course do better if you don't change water supplies. But the mineralization of water is widely variable, and it is not the distinction between distilled and undistilled but the particular concentration of particular minerals in particular water that is important. For example, if you're desperately short of calcium, 180 mg/day from water is going to be a lot better for you than 0 mg/day!

Short version: mineral content in water has a minimal to negligible impact in the context of good nutrition; it is possible for there to be enough of a mineral in a water supply to make a difference in the context of poor nutrition.

Rex Kerr
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    Interesting: In this answer we have a plausible-sounding speculation that the reduced minerals in the water would be covered by those in a balanced diet. In the accepted answer, we have a link to a WHO report which summarises experimental results, and says "Apparently the reduced mineral intake from water was not compensated by their diets, even if the animals were kept on standardized diet that was physiologically adequate in caloric value, nutrients and salt composition." Can you give reasons why we should ignore this experimental data over an (apparently untested) hypothesis? – Oddthinking Nov 07 '11 at 00:49
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    @Oddthinking - Did you read the report? Almost all the "data" is from a single study from the USSR, briefly summarized, with almost no information about experimental protocol. Unless someone can find the original article in Russian, I'm not sure we really have data. The rest is consistent with my summary that minerals in water can partially make up for poor nutrition but _not_ with the original claim that "distilled water can actually remove needed minerals from the body, due the lack of minerals in the water". (Calcium and magnesium seem to exert a mild protective effect.) – Rex Kerr Nov 07 '11 at 04:05
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    @RexKerr [This paper](http://www.sciencedirect.com/science/article/pii/S0278691507005716) claims that magnesium deficient diets are common enough for distilled water to be a problem. If that is the case, it is not so much that distilled water is an issue for those who already have mineral-balanced diets, but that deficient diets are common enough that distilled water can have negative health effects in the general populace. – called2voyage Jul 12 '16 at 13:46
  • @Oddthinking See above. – called2voyage Jul 12 '16 at 13:46
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    "Claim: Drinking distilled water can actually remove needed minerals from the body, due the lack of minerals in the water, and therefore do damage to the body." You're not actually addressing the claim. You're addressing poor nutrition, which is clearly not what the claim is referencing. –  Jul 13 '16 at 08:33
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    @RexKerr yet http://www.who.int/water_sanitation_health/dwq/nutrientschap12.pdf is **not** USSR - it's Czech Republic; also, Frantisek Kozisek is a professional scientist, as you can easily check here https://www.researchgate.net/profile/Frantisek_Kozisek/publications https://www.techneau.org/index.php?id=16 - the article itself being is heavily backed-up (65 references total), with most (if not all) references directly substantiating its claims. Although it's still a single source, it's a debate of *credible scientific source (of a scientist directly dealing with the subject)* vs *OR*. –  Aug 14 '16 at 16:38
  • tl;dr I'm with Oddthinking on this one: unless you provide any hard data backing your statements, your claims fall into "OR" category. –  Aug 14 '16 at 16:42
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    @vaxquis - I agree that given Skeptics' stance that inference from basic scientific principles is not really fair game, this is borderline "OR". Nonetheless, the article you cite doesn't, in my quick scan, really disagree with what I say above. It's stressing that there exist potential problems with distilled water (e.g. in pipes that don't get covered by a protective layer of calcium carbonate). It doesn't AFAICT have any direct data on distilled water leeching minerals from people with otherwise good nutrition, which is what the question was about. – Rex Kerr Aug 14 '16 at 23:14
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    @user26331 The original sources of the most extreme claims are all russian. The review is by a czech. But a quick read confirms precisely no attempt was made to judge the credibility of the sources and since the reviewer makes serious (and unreferenced) errors ("distilled water is very corrosive" WATF?) it seems fair to assume he didn't even have the expertise to judge their credibility even if he could be bothered to do so. – matt_black Jan 17 '20 at 21:00
11

In summary:

The available evidence suggests:

  • Drinking distilled water in usual amounts in everyday life, which includes regular meals, does not likely remove needed minerals from the human body in significant (harmful) amounts.
  • Drinking large amounts of distilled water in a short time can result in water intoxication, but the danger is about the same as with tap water.

This topic is covered by two reviews of literature with the opposing results: one by World Health Organization and one by Water Quality Association.

A review by World Health Organization

A 2005 report by World Health Organization (WHO), Chapter 12: Health risks from drinking demineralized water

This review includes an earlier statement by WHO from 1980:

Salts are leached from the body under the influence of drinking water with a low TDS. (TDS = total dissolved solids, which is basically mineral content.)

The author also says:

Results of experiments in human volunteers evaluated by researchers for the WHO report are in agreement with those in animal experiments and suggest the basic mechanism of the effects of water low in TDS (e.g. < 100 mg/L) on water and mineral homeostasis. Low-mineral water markedly: 1.) increased diuresis (almost by 20%, on average), body water volume, and serum sodium concentrations, 2.) decreased serum potassium concentration, and 3.) increased the elimination of sodium, potassium, chloride, calcium and magnesium ions from the body.

In the above paragraph, there is a mixture of things that don't go together: the increase of both "body water volume" and "diuresis," and increase of both "serum sodium concentration" and "elimination of sodium."

My only explanation is that they mixed the results of various types of studies. For example, drinking usual amounts of distilled water (compared to isotonic beverages) increases diuresis, but not the "body water volume" (Nutrients, 2017; Table 3 and 4). On the other hand, drinking excessive amounts (several liters) of any water, not just distilled, in a short time (few hours) increases the "body water volume" (Stat Pearls, 2019). These are two totally different scenarios, so the results in the above review seem to be really mixed up.

Next, in the report, every water with less than 100 mg minerals per liter seems to be considered demineralized, while by definition, demineralized water contains less than 10 mg minerals per liter (EPA.gov). About 80 cities from a list of 100 big US cities have less than 100 mg/L of minerals in tap water, so does this mean that their tap water is harmful for health?

A review by Water Quality Association

A 1993 review by Water Quality Association: Consumption of low TDS water is basically a critic of the already mentioned statement by WHO from 198O (refered below as the "Soviet report") that salts are leached from the body under the influence of drinking water with a low TDS.

It has been concluded that the consumption of low TDS water, naturally occurring or received from a treatment process, does not result in harmful effects to the human body.

Several types of scientific literature searches have found no harmful effects to the human body attributable to the consumption of low TDS water.

Review of the Soviet report has shown that the scientific methods used are questionable and the conclusions are either vague or unsupported by the data.

Many examples of real-world situations in which large populations have been and continue to be provided exclusively with low TDS water without any reported unusual or ill health effects, establishes the safety of consuming such waters by human beings.

Can drinking distilled water result in water intoxication (dilutional hyponatremia)?

Only if you drink it in large amounts in a short time; it can occur with any water, not just distilled water. Distilled water has no sodium and has low osmolality (0 mmol/kg), but this is very similar to tap water which usually has <10 mg sodium/liter (Mgwater) and osmolality as low as 3 mmol/kg (SGSM.ch, Table 2). A woman has died after drinking ~6 liters of regular water in 3 hours (Scientific American). A bit more in detail on Medical SE.

Does drinking distilled water dehydrate you?

No, distilled water can hydrate you about as well as average tap water, because, as said, distilled and tap water may not be that different in mineral content and osmolality. In general, the hydration potential of a beverage increases with its sodium content (as explained in another answer).

Jan
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  • I can't believe that this answer, which references the *literature* not just a single, implausible and internally incoherent review of dodgy papers with bad and unclear methods does not have more votes and is not the accepted answer. – matt_black Nov 11 '21 at 09:41
  • The Water Quality Association is a trade association of various suppliers of water treatment technology, most likely also including suppliers of reverse osmosis systems. Their [About WQA](https://wqa.org/about-wqa/) page says that "significant resources are being dedicated to independently conduct studies that _show the benefits of treated water_". This suggests one should assume them biased until proven otherwise. I certainly wouldn't consider them comparable to the WHO. – TooTea Mar 10 '23 at 15:27