The Core Issue: Mineral Depletion
Desalination is a crucial technology for producing fresh water from saline sources, but the process, particularly methods like reverse osmosis, removes not only salt but also vital minerals. These minerals, including calcium, magnesium, and iodine, are essential for numerous bodily functions, and their removal can lead to significant health complications over time. The resulting water, often similar to distilled water, is aggressive and highly unstable. In a phenomenon called 'leaching,' this water can draw minerals directly from the body's tissues and bones, exacerbating nutrient deficiencies.
Why Minerals in Drinking Water Matter
While the primary source of minerals should be a balanced diet, the minerals present in natural water are often in a more readily absorbed ionic form. For populations with diets already low in certain nutrients, drinking water can provide a crucial supplemental intake. For instance, studies have shown that a lack of sufficient magnesium in desalinated water contributes to higher rates of cardiovascular disease and type 2 diabetes in certain populations.
Health Risks of Un-remineralized Desalinated Water
- Cardiovascular Problems: Long-term consumption of soft, low-mineral water, particularly with low magnesium levels, has been linked to increased morbidity and mortality from cardiovascular disease. Magnesium is critical for heart function, and its deficiency can lead to significant health risks.
- Electrolyte Imbalance: The lack of electrolytes like sodium and potassium in demineralized water can disturb the body's salt-water balance. In extreme cases, this can lead to hyponatremia (low sodium levels), with symptoms including headache, fatigue, and muscle weakness.
- Bone Health Issues: Insufficient intake of calcium, which is removed during desalination, can negatively affect bone density and contribute to osteoporosis, particularly in vulnerable populations. The WHO has recommended minimum calcium levels in remineralized drinking water to mitigate this risk.
- Dental Health Decline: Some populations consuming desalinated water have reported declining dental health, partly due to low levels of calcium and fluoride in the water.
- Increased Toxin Exposure: The highly corrosive nature of demineralized water can cause it to leach toxic metals like lead from older plumbing systems. Minerals like calcium and magnesium have an anti-toxic action, and their absence increases the risk of absorbing other harmful substances.
- Mineral Loss in Cooking: Cooking with demineralized water can draw out essential minerals from food, including vegetables, meat, and cereals, further reducing nutritional intake.
Comparison of Water Types: Natural vs. Desalinated
This table illustrates the stark difference in mineral content between typical natural source water and un-remineralized desalinated water, highlighting why remineralization is necessary.
| Feature | Natural Tap Water (Varies by Source) | Un-remineralized Desalinated Water |
|---|---|---|
| Mineral Content | Contains varying levels of naturally occurring minerals like calcium, magnesium, and potassium. | Nearly devoid of all dissolved minerals and salts after processing, like reverse osmosis. |
| Taste Profile | Taste is influenced by mineral composition; often considered more palatable. | Described by some as 'flat' or 'unpleasant' due to the lack of minerals. |
| Corrosive Nature | Not typically corrosive to pipes due to mineral stability. | Highly aggressive and corrosive, potentially leaching metals from plumbing. |
| Health Effects (long-term) | Generally contributes to overall mineral intake. | Linked to mineral deficiencies and associated health risks, if not remineralized. |
| Stability | Relatively stable due to dissolved solids and balanced pH. | Unstable, potentially leading to material degradation in contact. |
The Critical Role of Remineralization
To address the significant health risks associated with mineral depletion, water authorities and treatment facilities must implement post-treatment remineralization. This process involves adding essential minerals back into the desalinated water to make it safe and palatable for consumption. Several countries heavily reliant on desalination, including Saudi Arabia and Israel, are already implementing or investigating remineralization processes to protect public health. The World Health Organization provides specific guidelines and has consistently called for targeted research to establish clear standards for mineral content in demineralized drinking water. The goal is to create a water product that is not only free of harmful pathogens and contaminants but also beneficial to human health, ensuring that the technology serves its purpose without creating unintended health consequences.
Conclusion
While desalination is an invaluable tool for combating water scarcity, the side effects of drinking desalinated water without proper remineralization are a serious public health concern. The removal of essential minerals like calcium and magnesium poses risks to cardiovascular and bone health, disrupts electrolyte balance, and can even increase exposure to toxic metals leached from plumbing. Authorities must ensure robust remineralization protocols are followed to produce water that is not only pure but also contains the necessary minerals for safe, long-term human consumption. Consumers should also be aware of their water source and consider supplementation if necessary.
For more detailed guidance, consult the World Health Organization's document on the health risks of demineralized water: Health Risks From Drinking Demineralised Water.
