Demineralized water FAQ Frequently Asked Questions

What is demineralised water?
Can water be enriched with minerals?
Why is demineralised water not suitable for consumption?
What supports this theory?
Is distilled water suitable for cooking?
Which are the health risks from consumption of demineralised or low-mineral water?
Is there any theory which supports distilled water consumption?
Why do these previous affirmations lack credibility?

What is demineralised water?

Demineralised water is water completely free (or almost) of dissolved minerals as a result of one of the following processes:

  • distillation

  • deionization

  • membrane filtration (reverse osmosis or nanofiltration)

  • electrodyalisis

  • or other technologies.

The amount of dissolved solids in water that has followed one of these processes could be as low as 1 mg/l and is in any case always less than 10 mg/l. The electrical conductivity is generally less than 2 mS/m and may be even lower (< 0,1 mS/cm).

Can water be enriched with minerals?

Due to the water shortages in some regions of the world (Middle East, for example), seawater is used to produce drinking water by a desalination process in more than 7.500 desalination plants worldwide. This desalinated or demineralised water is in most of the cases enriched with some minerals before it is packaged in bottles, tetra bricks or even plastic bags to be consumed by people. The aim of this mineral enrichment is to make the water fully appropriate for consumption.

Why is demineralised water not suitable for consumption?

There are three evident reasons:

  1. Demineralised water is highly aggressive.
    Its distribution through pipes and storage tanks is not possible because the aggressive water would leach metals and other materials from the pipes and other plumbing materials.
  2. Demineralised water has poor taste and thirst-quenching characteristics.
    This is again due to its lack of minerals.
  3. Demineralised water has been proven to have adverse health effects for humans, due to the deficency of certain constituents. This is further documented in the following paragraph.

What supports this theory?

There are a number of studies, conducted by health professionals in different parts of the world, which support the three statements above. Here is an example of some of these studies and the resulting conclusions:

  • Rahmmanin et al, 1989. Study conducted on rats. Conclusions: distilled water caused decreased secretion of tri-iodothyronine and aldosterone, increased secretion of cortisol, morphological changes in the kidneys (including a more pronounced atrophy of glomeruli), swollen vascular endothelium limiting the blood flow and reduced skeletal ossification in fetuses.

  • Studies conducted on human volunteers by the WHO, 1980. Conclusions: low mineral water consumption increased diuresis (almost by 20%, on average), body water volume and serum sodium concentrations, decreased serum potassium concentration, increased sodium elimination.

  • Robbins and Sly, 1981. Study conducted in patients who received balanced intravenous nutrition diluted with distilled water. Conclusion: The intake of low mineral water is presumed to be responsible for an increased elimination of minerals from the body.

  • Study conducted by Basnyat et al, 2000. Conclusion: Ingestion of several liters of low-mineral water following intense physical efforts may cause severe acute damage, such as hyponatremic shock or delirium.

  • Epidemiological studies by Sauvant and Pepin 2002; Donato et al. 2003; Monarca et al. 2003; Nardi et al. 2003. Conclusion: Soft water and water low in magnesium is associated with increased morbidity and mortality from cardiovascular disease.

  • Study conducted by Verd Vallespir et al.1992. Conclusion: Intake of water low in calcium is associated with higher risk of fracture in children.

  • Jacqmin et al.1994. Conclusion: Intake of water low in calcium is associated with certain neurodegenerative diseases.

  • Yang et al. 1997, 1998, 2002. Conclusion: Intake of water low in calcium is associated with pre-term birth, low weight at birth and some types of cancer.

…and a very long etcetera of properly conducted experiments, which demonstrate what the World Health Organization is also claiming:

The WHO published in its latest report available (2004), that 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.

Is distilled water suitable for cooking?

As we explained before in this page, distilled water is very low in mineral content. When cooking any vegetable rich in minerals in demineralised water, a negative osmotic pressure appears on the vegetable which makes it loose all its minerals in behalf of the water. That is, the vegetable would loose all its minerals, which would pass on to the water, which is then thrown away into the sink. As a result, we would be eating vegetables laking on essential minerals.

In brief: cooking foods in distilled water lowers their nutrient value.

Which are the health risks from consumption of demineralised or low-mineral water?

Here are some of the proven risks of demineralized water or water low in minerals:

  • decreased secretion of tri-iodothyronine and aldosterone

  • increased secretion of cortisol

  • morphological changes in the kidneys (including a more pronounced atrophy of glomeruli)

  • swollen vascular endothelium limiting the blood flow

  • reduced skeletal ossification in fetuses

  • increased diuresis (around 20%)

  • increased body water volume

  • increased elimination of minerals from the body

  • hyponatremic shock or delirium

  • increased morbidity and mortality from cardiovascular disease

  • higher risk of fracture in children

  • neurodegenerative diseases

  • pre-term birth

  • low weight at birth

  • some types of cancer

Is there any theory which supports distilled water consumption?

In spite of all this clear evidence set out above, there is still a controversy going on about the so-called benefits of distilled water, some people defending surprising “theories” like the following:

  • Distilled water will not leach minerals from your body. It is perfectly safe to drink. Distilled water does not taste bland or flat. Joe Letorney Jr., B.S. degree in marketing

  • 'You're safer with distilled bottled water," Gary R. Rose, a treatment and research representative at the AIDS Action Council

  • "One of the fundamental differences between distillation and all other types of water purification is that distillation is very reliable. If the distiller is operating, the quality of the water it produces will be consistent. There is no decrease in performance over time." Colin Ingram, The Drinking Water Book.

However, as far as Lenntech could know, none of these statements have been supported by any actual experiment, reason why they lack credibility.

Why do these previous affirmations lack credibility?

There is no doubt that personal and cultural beliefs influence both our perceptions and our interpretations of reality. It is because of this that scientifics developed some standard criteria and procedures, which aim to minimize those influences when developing a theory. It's the "scientific method", which follows 4 steps:

1. Observation and description of a happening.

2. Formulation of an hypothesis (tentative description) to explain the happening and which is consistent with the observation.

3. Use of the hypothesis to predict other happenings of the same kind.

4. Proper performance of experimental tests of the predictions by several independent experimenters.

5. Repeat steps 3 and 4 until there are no discordances between theory, experiment and observation.

The statements of Joe Letorney Jr., Gary R. Rose and Colin Ingram are missing the last two steps of the scientific method.

Any assumption which hasn't followed these steps, cannot be considered as a valid theory.

Check our demi water web page or click here for a more detailed explanation about health risks of drinking demineralized water.

For water terminology check out our Water Glossary or go to water FAQ overview.

Feel free to contact us if you have any other questions







Lenntech BV

Rotterdamseweg 402 M
2629 HH Delft
The Netherlands

tel: +31 152 610 900

fax: +31 15 261 62 89

e-mail: info@lenntech.com











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