The Conundrum of Demineralized Water
ZeroWater's advanced 5-stage filtration system utilizes ion-exchange technology to remove nearly 99.6% of total dissolved solids (TDS) from tap water. The goal is to provide a pure-tasting water free of common contaminants like lead, mercury, and certain "forever chemicals". The accompanying TDS meter allows users to verify this level of purity, which is often seen as a sign of superior water quality.
However, the term "total dissolved solids" is not discriminatory. It encompasses both harmful substances and beneficial minerals that the human body needs. Long-term consumption of demineralized water, which lacks essential minerals, has raised concerns among health organizations and researchers.
Mineral Deficiencies
One of the most significant potential side effects is the risk of mineral deficiency. While most of our mineral intake comes from food, water can provide supplementary amounts that are more easily absorbed by the body due to their free-ion state.
- Calcium and Magnesium: Prolonged consumption of low-mineral water is linked to deficiencies in calcium and magnesium. Studies have associated low levels of these minerals from drinking water with increased risk of cardiovascular disease, impaired nerve and muscle function, and reduced bone mineral density, potentially increasing the risk of osteoporosis and fractures.
- Electrolyte Imbalance: The body tightly regulates its electrolyte balance. Consuming water devoid of minerals and electrolytes can disrupt this balance, potentially leading to increased urination and thirst. In extreme cases, this can result in hyponatremia (low sodium levels), a dangerous condition, though this typically requires ingesting very large amounts of water over a short period.
Corrosive Nature and Contaminant Leaching
Water that is low in dissolved minerals is naturally aggressive and can leach metals from pipes and plumbing fixtures. This can result in increased dietary intake of toxic metals like lead and copper, particularly in older homes with outdated plumbing. While the ZeroWater filter itself is certified to reduce lead, the demineralized water it produces could potentially pick up contaminants after it has been filtered and stored in contact with certain materials.
Risks from Expired Filters
It is critical to replace ZeroWater filters promptly when the included TDS meter reads 006 or higher. Continuing to use an expired filter can pose its own set of health risks:
- Contaminant Release: As a filter becomes saturated, it can no longer effectively trap contaminants. In some cases, a phenomenon known as "dumping" can occur, where the filter releases trapped impurities back into the water.
- Bacterial Regrowth: The granular activated carbon and ion-exchange resins inside the filter can become breeding grounds for bacteria, especially if the filter is not maintained properly or is used past its lifespan.
- Taste and pH Changes: An expired filter can impart a noticeably strange, often sour or fishy, taste to the water. The filter's exhausted ion beads may also cause a drop in the water's pH, which is an indicator that it's no longer working correctly.
Effects on Cooking
Cooking food in demineralized water can reduce the nutritional value of the meal. The absence of minerals in the water creates an osmotic pressure gradient, causing essential minerals to be drawn out of the food and into the surrounding water. For example, cooking vegetables in soft water can lead to a significant loss of magnesium, calcium, and other trace elements that are then discarded when the water is drained.
Side Effects Comparison: ZeroWater vs. Other Water Sources
| Feature | ZeroWater (0 TDS) | Standard Tap Water (Municipal) | Remineralized Filtered Water |
|---|---|---|---|
| TDS Level | Approximately 0-5 ppm (parts per million) | Varies greatly; can be up to 500+ ppm | Varies, typically 50-200 ppm (palatability) |
| Mineral Content | Virtually none, stripped during filtration | Varies, can contain essential minerals | Replenished to beneficial levels after filtration |
| Taste | Often described as flat or insipid due to lack of minerals | Varies depending on source; can have chlorine taste | Crisp and palatable; minerals enhance taste |
| Potential Health Risks | Mineral deficiency, electrolyte imbalance, corrosive to pipes | Presence of contaminants (lead, PFAS, chlorine) if untreated | Generally low risk if remineralized properly; avoids demineralized water issues |
Conclusion: Weighing the Purity vs. Health Trade-off
ZeroWater filters are highly effective at removing a wide range of contaminants, offering a peace of mind that tap water may not provide. However, this extreme level of filtration, which results in demineralized water, is not without potential drawbacks. The long-term effects of consuming water stripped of essential minerals include a risk of deficiencies and other health issues, especially for vulnerable populations. For those who rely on ZeroWater, ensuring adequate mineral intake through a balanced diet or considering a separate remineralization process is highly recommended to counteract these potential side effects. It is a careful trade-off between absolute purity and the nutritional needs that can be partially met through drinking water. For further reading, an expert consensus report can be found here: Demineralization of drinking water: Is it prudent?.
