Understanding Demineralized Water
Demineralized water, which is water with its mineral salts removed, is produced through processes such as distillation, reverse osmosis (RO), and deionization. While this removes harmful impurities, it also strips away essential minerals like calcium, magnesium, and potassium that are vital for human health. The resulting water has a low total dissolved solids (TDS) count and is aggressive and highly corrosive, seeking to pull minerals from whatever it contacts. This unique chemical property drives many of the long-term health concerns associated with its regular consumption.
Major Long-Term Health Consequences
Mineral Deficiencies (Calcium and Magnesium)
Long-term drinking of demineralized water can cause deficiencies in crucial minerals, even with an otherwise balanced diet. While drinking water may not be our primary source of minerals, those found in water are in a bioavailable ionic form and are more readily absorbed by the body than those in food. A lack of these minerals can have widespread effects:
- Calcium: Essential for bone structure, teeth, blood clotting, and nerve and muscle function. Studies have linked low-calcium water with a higher risk of fracture in children and osteoporosis in adults.
- Magnesium: A cofactor in over 300 enzymatic reactions, crucial for heart and muscle contractility, neuromuscular excitability, and protein synthesis. Magnesium deficiency is linked to cardiovascular disease, motor neuronal diseases, and pregnancy disorders.
Electrolyte Imbalance and Homeostasis Disruption
The body tightly regulates its water and electrolyte balance, a process known as homeostasis. Demineralized water's lack of electrolytes forces the body to pull minerals from its own reserves to maintain this balance. Experiments on humans and animals show that low-mineral water can increase urine output, leading to the excessive elimination of sodium, potassium, calcium, and magnesium. Over time, this imbalance can cause a range of symptoms and conditions:
- Tiredness and weakness
- Headaches
- Muscle cramps
- Cardiovascular disorders
- In severe cases, acute hyponatremic shock (water intoxication), especially after intense physical exertion.
Cardiovascular Disease Risks
Research has repeatedly linked low-mineral or soft water with increased cardiovascular disease (CVD) morbidity and mortality. A study on children drinking very low-mineral water showed elevated homocysteine levels and altered lipid profiles, both risk factors for future CVD. The protective effect of magnesium from hard water is often cited as a key reason for this link.
Increased Risk of Toxic Metal Intake
Demineralized water's aggressive, corrosive nature is a known problem for plumbing systems, as it can leach metals like lead and cadmium from pipes, fittings, and storage tanks. A lack of minerals like calcium and magnesium also reduces water's ability to protect against the absorption of these toxic elements. This can increase dietary intake of harmful metals, posing additional health risks.
Impact on Cooking and Food Nutrients
Using demineralized water for cooking further compromises dietary intake of essential minerals. The osmotic pressure gradient between the mineral-deprived water and food causes minerals to leach from vegetables, meat, and cereals into the cooking water. Studies have shown cooking with demineralized water can cause substantial losses of up to 60% of calcium and magnesium, and even higher percentages for other microelements.
Comparison: Demineralized vs. Mineralized Water
| Feature | Demineralized Water | Mineralized Water |
|---|---|---|
| Mineral Content | Almost none | Variable, contains essential minerals like Ca, Mg |
| Taste | Flat, lacking flavor due to no minerals | Flavorful due to minerals and dissolved solids |
| Corrosiveness | Highly corrosive, leaches metals from pipes | Non-corrosive (or less so), stabilizes pipes |
| Health Impact | Associated with nutrient loss and health risks | Contributes essential minerals to diet, protective effects |
| Use | Industrial, laboratory, or specific medical needs | Everyday drinking, cooking, hydration |
Special Considerations for Vulnerable Groups
Infants and young children are particularly susceptible to the negative effects of demineralized water. Giving infants beverages prepared with distilled or low-mineral water can lead to serious health issues, including metabolic acidosis, delirium, and impaired development. Reduced skeletal ossification was observed in rat studies where pregnant mothers consumed distilled water. For pregnant women, low-mineral water intake is associated with conditions like preeclampsia and potential complications for the newborn.
Conclusion: The Final Word on Demineralized Water
In summary, while water purification techniques like reverse osmosis have their place in providing safe, clean water, the long-term effects of drinking demineralized water without remineralization can pose significant health risks. From mineral deficiencies and electrolyte imbalances to potential cardiovascular and bone health issues, the evidence points to a cautious approach. It is recommended to choose water that contains a balanced mineral content to support long-term health. If using a home demineralization system, consider a unit with a remineralization stage or supplement your diet adequately to compensate for the lack of minerals. Further research is ongoing, but the precautionary principle suggests avoiding long-term, exclusive consumption of water devoid of its natural minerals. For additional information on water quality, refer to the World Health Organization's report on health risks from demineralized water(https://www.purahome.com/blog/wp-content/uploads/2015/12/WHO-Nutrients-in-Water.pdf).
