Understanding Low Mineral Water
Low mineral water, often referred to as demineralized, deionized, or reverse osmosis (RO) water, is water that has had most or all of its dissolved mineral content removed. While this process effectively strips away harmful contaminants and impurities, it also eliminates beneficial minerals such as calcium, magnesium, and potassium that are naturally present in water. This process is common in home water filtration systems and in the production of some bottled waters. The resulting water has a very low Total Dissolved Solids (TDS) count, which can sometimes be incorrectly marketed as superior or 'purer' water.
How Water Loses its Minerals
The most common method for creating demineralized water is Reverse Osmosis (RO), which forces water through a semi-permeable membrane. This process effectively blocks larger molecules and ions, including most minerals. Distillation, which involves boiling water and condensing the steam, also removes nearly all dissolved solids. While these methods are excellent for removing impurities like lead, arsenic, and nitrates, they do not discriminate between harmful substances and essential minerals.
The Risks of Long-Term Consumption
For a long time, the impact of drinking demineralized water was not fully understood, but research, including a World Health Organization (WHO) report, has shed light on potential health concerns associated with its long-term consumption.
Mineral Deficiency and Homeostasis Disruption
- Leaching of Minerals: Demineralized water is aggressive and seeks to balance itself by absorbing minerals from its surroundings. When consumed, this means it can leach essential minerals directly from the body's tissues, including bones and teeth, and even from food cooked in it.
- Compromised Mineral Balance: The lack of minerals can disrupt the body's water and mineral metabolism, affecting fluid balance and the excretion of critical ions. This can lead to increased urination and a higher excretion of essential electrolytes like sodium, potassium, and magnesium, potentially causing an electrolyte imbalance.
Impact on Bone and Dental Health
Multiple studies have linked the consumption of low mineral water with negative effects on bone and dental health, especially in children. A study published in The Journal of Nutrition found that children drinking very low mineral water had lower daily calcium intake, slower height increase, and reduced bone mineral content compared to those drinking normal water. The lack of calcium and fluoride in demineralized water has also been associated with an increased risk of dental caries.
Possible Gastrointestinal and Cardiovascular Issues
Some evidence suggests that consuming demineralized water with a slightly acidic pH may cause or exacerbate gastrointestinal issues, including chronic gastritis and ulcers. Additionally, numerous epidemiological studies have reported an association between soft water (low in calcium and magnesium) and an increased risk of cardiovascular disease, though more research is needed to fully establish causality.
Limited Benefits of Low Mineral Water
Despite the risks, proponents of low mineral water often cite a few potential benefits, though these are often debated and largely unproven by robust scientific evidence. Most benefits are associated with the cleanliness of the water, not its low mineral content.
- Removes Contaminants: When using an RO system or distillation, the water is effectively stripped of many pollutants, pesticides, and other contaminants, providing a very clean source of water where tap water quality is poor.
- Potential for Detoxification: Some sources, not backed by widespread scientific consensus, suggest that low mineral water's 'empty' nature allows it to absorb and flush out more toxins from the body. However, this is largely anecdotal and not supported by peer-reviewed studies.
- Slightly Improved Taste: For some, the pure, flat taste of demineralized water is preferable to the taste of tap water, which can be affected by chlorine and mineral content.
Comparison: Low Mineral vs. Mineral Water
To better understand the differences, consider this comparison table:
| Feature | Low Mineral Water | Mineral Water |
|---|---|---|
| Mineral Content | Very low to non-existent (usually < 100 mg/L TDS). | Contains significant amounts of dissolved minerals like calcium, magnesium, and potassium (varies, often > 500 mg/L TDS). |
| Source | Produced via purification methods like reverse osmosis, distillation, or deionization. | Sourced from natural springs or underground aquifers, with mineral content derived naturally. |
| Effect on Health | Potential risks include mineral deficiencies, bone/dental issues, and disturbed fluid balance. | Supports essential bodily functions and helps contribute to daily mineral intake. |
| Preparation | Often created at home with water filtration devices or bought as purified bottled water. | Typically bottled at the source with minimal processing to preserve natural mineral content. |
| Taste | Often described as flat or bland due to the absence of dissolved minerals. | Taste is influenced by its specific mineral composition, which varies by source. |
How to Remineralize Your Water
If you use an RO system or prefer purified water, you can take steps to add beneficial minerals back into it. This is a practice endorsed by health organizations and experts to mitigate the risks of drinking demineralized water.
- Remineralization Filters: Many reverse osmosis systems offer an optional remineralization cartridge that adds minerals like calcium and magnesium back into the water after filtration.
- Mineral Drops: Concentrated mineral drops can be added to water to boost its mineral content. These drops are available from health food stores and online.
- Alkaline Water Filters: Pitcher-style alkaline filters often contain mineral-rich media that remineralize and raise the pH of purified water.
- Dietary Compensation: A well-balanced diet rich in fruits, vegetables, and dairy can help compensate for the mineral deficit in water, though the bioavailability of minerals from water is often higher.
Conclusion
While low mineral water is highly effective at removing contaminants, it is not an ideal source of hydration for long-term, exclusive consumption due to its lack of essential minerals. The evidence suggests that potential health risks, such as mineral deficiencies and negative impacts on bone health, outweigh the limited benefits. For those concerned about water purity, a balanced approach is recommended: use an effective filtration method to remove contaminants, but ensure the water is remineralized afterward or that your diet sufficiently replaces lost minerals. Informed choices about your water source are critical for overall health and well-being. For more detailed information on water quality, consult trusted sources like the World Health Organization.
