Understanding Demineralized Water
Demineralized treated water is water that has had its mineral ions—such as calcium, magnesium, sodium, and chloride—removed through purification processes. The most common methods for this are deionization and reverse osmosis. Unlike distilled water, which is boiled and condensed, demineralization focuses on removing charged mineral particles using ion exchange resins or membranes. This makes the water ideal for industrial applications where mineral buildup and conductivity are issues, such as in laboratories, power plants, and manufacturing. However, what makes it useful for industry makes it problematic for human consumption.
The Health Risks of Drinking Demineralized Water
While short-term or occasional consumption of demineralized water is not typically dangerous, relying on it as your primary source of hydration poses several potential health risks. The absence of essential minerals, which are crucial for numerous bodily functions, is the primary concern. These are not just trace elements; they play a vital role in maintaining electrolyte balance, supporting bone health, and regulating cardiovascular function. A diet rich in minerals can compensate, but relying on food alone may not be enough for all individuals.
- Mineral Deficiencies: A diet deficient in calcium and magnesium from water can contribute to bone health issues and other long-term problems. Water is a bioavailable source of these minerals, and their removal can increase the risk of developing a deficit.
- Cardiovascular Issues: Studies have suggested a link between soft, low-mineral water and increased morbidity and mortality from cardiovascular disease. Magnesium, in particular, is noted for its protective effect on the cardiovascular system.
- Aggressive Nature and Toxicity: Demineralized water is aggressive and can leach metals like lead from plumbing materials, increasing the intake of toxic metals. This corrosive property is a major reason it is treated for industrial use but discouraged for drinking.
- Incomplete Contaminant Removal: Some demineralization methods, particularly deionization, do not remove all types of contaminants. Uncharged organic compounds, viruses, and bacteria may remain, posing a health risk.
- Poor Taste and Hydration: Lacking minerals, demineralized water has a flat, unappealing taste that some find hard to tolerate. It also lacks the electrolytes needed for efficient hydration, especially after physical exertion.
Potential Effects on the Body
When the body consumes water with a very low mineral content, it can disrupt the body's mineral homeostasis, the system that regulates mineral and water balance. This can lead to a state of compromised metabolism and electrolyte imbalance. For example, the intake of low-mineral water is associated with an increase in diuresis (urination) and a change in serum potassium and sodium concentrations. Chronic imbalances can exacerbate existing health conditions or contribute to new ones, from digestive issues to weakened immune function.
It is important to note that the immediate effects of drinking demineralized water, such as a mild laxative effect from high magnesium water, are very different from the long-term consequences of consistent low-mineral water consumption. Regular intake of demineralized water is a far greater risk than a one-off instance.
How Treated Water Compares
While demineralized water is often an endpoint for industrial uses, residential systems often produce different results or include a remineralization stage. Understanding the differences is key to making an informed choice for your home.
| Feature | Demineralized Water (DI/RO) | Mineral Water (Natural Source) | Remineralized Water (Post-treatment) |
|---|---|---|---|
| Mineral Content | Almost zero mineral ions removed artificially | Naturally contains essential minerals like calcium, magnesium | Demineralized water with minerals added back |
| Taste Profile | Bland, flat, or unusual due to lack of minerals | Crisp and fresh, influenced by natural mineral composition | Can be improved, but may not fully replicate natural mineral water taste |
| Health Impact | Long-term use can lead to mineral deficiencies and health risks | Supports hydration and provides natural minerals for health | Safer than demineralized, but the added minerals may not be as bioavailable |
| Best Use Case | Industrial, laboratory, cosmetic, and automotive applications | Daily hydration for general health and well-being | Affordable and safe drinking water for households with RO systems |
| Purity | High purity (low TDS), but may not remove all pathogens | Naturally pure and filtered, regulated for safety | Varies based on the source water and remineralization process |
The Role of Remineralization
As seen in many modern home RO systems, remineralization is a critical step to make purified water suitable for drinking. This process adds a blend of beneficial minerals back into the water after purification, mitigating the health risks associated with a low-mineral intake. This not only makes the water healthier but also improves the taste, making it more palatable. If you have a reverse osmosis system at home, ensure it has a remineralization stage to protect your health.
Conclusion
While demineralized water is a powerful tool for industrial and specialized applications, it is not suitable for long-term daily consumption due to the absence of crucial minerals. The health risks, including potential mineral deficiencies, cardiovascular issues, and the corrosive nature of the water, far outweigh any perceived benefits for regular drinking. For daily hydration, your best options are natural mineral water or treated water that has been remineralized to provide a balance of essential electrolytes and flavor. Always prioritize water that supports, rather than depletes, your body's nutritional needs.
The World Health Organization's Recommendations
In a comprehensive report on the health risks of drinking demineralized water, the World Health Organization (WHO) has addressed the need for guidelines on minimum mineral content in desalinated drinking water. The report notes that early studies observed adverse effects in rats, dogs, and human volunteers consuming water with very low total dissolved solids (TDS). For example, a 1980 WHO report recommended a minimum TDS level of 100 mg/L, with an optimum range of 200-500 mg/L. They also suggested minimum levels for calcium (30 mg/L) and bicarbonate (30 mg/L) to ensure both health benefits and reduced corrosivity. More recent research cited in the report recommends a minimum of 10 mg/L for magnesium and 20 mg/L for calcium.
This authoritative guidance underscores the scientific consensus that plain demineralized water should not be considered a viable long-term drinking source without proper remineralization. The WHO's findings indicate that while short-term consumption may not pose an immediate threat, consistent intake of low-mineral water compromises essential bodily functions and is linked to chronic health issues, from cardiovascular problems to neurodegenerative diseases. For this reason, many countries now regulate the mineral content of public and bottled water to ensure it is safe and healthy for regular consumption.
The Aggressive Nature of Demineralized Water
The corrosive characteristic of demineralized water is a significant concern that extends beyond just plumbing. Because it lacks dissolved minerals, it is chemically "hungry" and will aggressively seek to leach minerals from any material it contacts, including metal pipes and containers. This process can introduce toxic metals into the water, such as lead or cadmium, which are then ingested. For consumers, this means that even if the water is free of minerals initially, it can become contaminated during storage and distribution. This aggression is also a key reason why it is used in industries to prevent scaling in machinery but is treated with inhibitors for safe use in specific industrial contexts. The solution for drinking water is to restore the mineral content, making it stable and less corrosive.
Demineralized Water vs. Distilled Water
It is common to confuse demineralized and distilled water, but they are produced differently and have varying characteristics.
- Demineralized Water: Typically produced via ion exchange or reverse osmosis, this water has had its mineral ions removed. However, some processes, like deionization, may not remove uncharged particles such as bacteria and viruses.
- Distilled Water: Made by boiling water and collecting the steam, which is then condensed back into liquid. This process removes not only minerals but also bacteria, viruses, and most organic compounds. However, it is energy-intensive and can still contain some volatile organic compounds.
Both types are unsuitable for long-term human consumption without remineralization due to the lack of essential minerals. Distilled water might be purer from a microbiological standpoint, but neither provides the health benefits of mineral-rich water.
How to Safely Consume Demineralized Water
If your only source of water is demineralized (such as from a home RO system without remineralization), there are ways to make it safer for long-term drinking. The most direct method is adding mineral drops or supplements, which are widely available. These drops contain concentrated minerals, allowing you to control the exact balance and restore the water's taste and nutritional value. For those cooking with demineralized water, be aware that it can leach minerals from food, so cooking with mineral-rich water or supplementing your food is a better approach to preserve nutrients. Ultimately, a balanced diet is crucial, but supplementing your water is an effective way to address the missing minerals.
Note: This information is for educational purposes. Consult a healthcare professional or water quality specialist for personalized advice, especially if you rely on a non-standard water source. For more detailed information, consider reading reports from the World Health Organization on water quality.
