The statement that water 'increases calcium' isn't quite accurate in the way we might think. Water doesn't produce calcium in the body, but it can be a significant source of dietary calcium, and proper hydration is essential for the body's calcium absorption and utilization processes. The amount of calcium contributed by water varies dramatically based on its mineral content, which is influenced by its geological source.
The Science of Water and Minerals
Water, known as the universal solvent, picks up minerals as it moves through rocks and soil. This natural process is responsible for the mineral content of our drinking water. Groundwater, in particular, often contains dissolved calcium and magnesium from limestone, chalk, and dolomite. The higher the concentration of these minerals, the 'harder' the water. The amount of calcium in tap water can vary widely between different cities and regions, meaning some areas naturally have a built-in source of supplemental calcium, while others have very little. Mineral water from specific springs is often naturally rich in calcium and other beneficial minerals.
The Bioavailability of Calcium in Water
Perhaps the most surprising aspect of calcium in water is its high bioavailability. Studies have shown that the body can absorb the calcium from water as effectively as, or even better than, the calcium found in dairy products. This is because the calcium in water is in its ionic (dissolved) form, which is readily absorbed in the gastrointestinal tract. Furthermore, since people tend to consume water in small, frequent amounts throughout the day, the body can absorb the calcium more efficiently compared to taking a large single dose from a supplement.
Hydration's Crucial Role in Bone Metabolism
Beyond its role as a mineral source, adequate hydration is a fundamental requirement for maintaining bone health. Bones are dynamic tissues that constantly undergo a process called remodeling, where old bone is broken down and new bone is formed. Water is essential for this process and acts as the primary transport vehicle for calcium and other vital nutrients to the bones. Dehydration, on the other hand, can negatively affect bone health in several ways:
- It can increase the level of parathyroid hormone (PTH), which can trigger the body to draw calcium from the bones to increase blood calcium levels.
- Dehydration impairs the function of osteoblasts and osteoclasts, the cells responsible for bone remodeling.
- It can lead to a buildup of toxins that can cause inflammation and bone deterioration.
- Proper fluid levels are also necessary for the synovial fluid that lubricates joints and for cartilage that acts as a shock absorber.
Hard Water vs. Soft Water
This is a comparison of hard and soft water characteristics:
| Feature | Hard Water | Soft Water |
|---|---|---|
| Mineral Content | High in dissolved calcium and magnesium. | Low in calcium and magnesium, often high in sodium. |
| Dietary Calcium | Potentially significant dietary source, especially for those with low intake. | Negligible contribution to calcium intake. |
| Health Effects | Linked with cardiovascular benefits and bone health. Not considered a health risk. | Does not pose a direct health hazard, but lacks beneficial minerals. |
| Sodium Content | No added sodium unless artificially softened. | Can increase sodium intake, which may be a concern for some. |
| Household Issues | Causes limescale buildup on appliances and fixtures. | Does not cause scale, but can feel slick or slimy on skin. |
The Impact of Filtration and Softening on Water Calcium
For households and municipalities, the mineral content of water can be managed through various treatment methods. Some common options include:
- Water softeners: These systems use an ion exchange process to replace calcium and magnesium ions with sodium or potassium ions, effectively removing the hardness but adding sodium.
- Reverse osmosis (RO) systems: RO uses a semipermeable membrane to filter out nearly all dissolved impurities, including minerals like calcium. The resulting water is almost pure, or demineralized.
- Activated carbon filters: Found in most standard pitcher filters, these primarily remove contaminants like chlorine, but have little to no effect on dissolved minerals like calcium.
- Boiling water: While boiling water kills pathogens, it concentrates minerals like calcium as the water evaporates, potentially increasing the calcium level in the remaining volume.
Water as a Supplement: Is it Enough?
While consuming mineral-rich water can contribute to your daily calcium intake, it's crucial to understand its role. For most people, water contributes only a small fraction of the total recommended daily calcium intake, which for many adults is between 1,000 and 1,200 mg. In areas with hard water, this contribution can be more substantial, but it should not be relied upon as the sole source. Instead, it serves as a supplement that complements a balanced diet rich in other calcium sources like dairy, fortified foods, and leafy green vegetables.
Conclusion
To answer the question, water itself does not increase calcium, but mineral-rich water can serve as a highly absorbable source of dietary calcium. Adequate hydration is also a vital mechanism for ensuring the body can properly utilize the calcium it consumes, with dehydration having negative effects on bone metabolism. While water can be a valuable supplement to your mineral intake, it is not a replacement for a balanced, calcium-rich diet. The bioavailability of calcium from water, coupled with the importance of consistent hydration, highlights the often-underestimated role of water in maintaining strong bones and overall health.
