Purified water is water that has undergone a mechanical process to remove nearly all impurities and dissolved solids. Common methods include distillation and reverse osmosis (RO), which forces water through a fine membrane. Deionized water is another form where almost all ion-forming mineral salts have been removed. While these processes effectively eliminate contaminants like heavy metals and pathogens, they also strip away beneficial, naturally occurring components. This high degree of purity, often measured by a near-zero total dissolved solids (TDS) level, is why health concerns arise from consistently drinking this type of water.
The Core Deficiency: Essential Mineral Removal
Purification processes remove between 98% and 100% of naturally present minerals, including Calcium and Magnesium. Calcium is fundamental for maintaining bone density, facilitating nerve signal transmission, and supporting muscle contraction. Magnesium is also important, aiding in over 300 enzyme reactions, regulating blood pressure, and contributing to cardiovascular health.
Although diet is the primary source for these minerals, water can contribute a notable fraction of the daily required intake. When this mineral contribution is removed, the body may not be able to compensate entirely through food intake alone. Using demineralized water for cooking can exacerbate the problem, as it leaches essential elements from foods like vegetables, meat, and cereals. This leaching effect can cause losses of Magnesium and Calcium from food that may reach as high as 60%, significantly reducing the meal’s nutritional value.
Increased Acidity and pH Changes
Purified water is devoid of dissolved mineral salts and lacks the natural buffering capacity found in tap or spring water. This absence of buffering agents means the water’s pH is highly susceptible to environmental changes. When exposed to the atmosphere, this pure water readily absorbs carbon dioxide (CO2) from the air. The dissolved carbon dioxide reacts with water to form a weak acid called carbonic acid (H2CO3).
The formation of carbonic acid causes the water’s pH to drop from a neutral 7.0 to a slightly acidic range, often between 5.5 and 6.9. While the body maintains a tightly regulated internal pH, the consistent intake of water with a lower pH value is a subject of discussion regarding long-term physiological impact. The concern relates to the water’s corrosive nature and its lack of balancing minerals.
The Mechanism of Loss: Osmotic Pressure
A theory regarding purified water involves osmotic pressure, which describes the movement of water across a semipermeable membrane. Osmosis is the process where water moves from an area of low solute concentration to an area of high solute concentration to achieve equilibrium. The body’s internal fluids, such as blood, have a specific concentration of dissolved salts and electrolytes.
Water that is essentially pure, with a near-zero concentration of total dissolved solids (TDS), is considered hypotonic relative to the body’s fluids. When consumed, this hypotonic water enters the digestive system and encounters the solute-rich environment of the gut lining. Osmosis suggests that the pure water will attempt to balance this osmotic gradient by pulling electrolytes and minerals from the body’s tissues into itself. This represents a theoretical active removal of existing body minerals, such as sodium and potassium, from the body’s reserves.
Long-Term Health Consequences of Exclusive Consumption
Sustained consumption of demineralized water, particularly as the sole source of hydration, is associated with various health risks. The long-term absence of Calcium and Magnesium intake from water is linked to an elevated risk of certain conditions. Studies suggest an association between drinking water low in these elements and a higher risk of bone fractures and cardiovascular issues.
The leaching effect, combined with the lack of mineral replenishment, can lead to a gradual electrolyte imbalance. Early symptoms of this imbalance may manifest as generalized tiredness, persistent weakness, and headaches. More pronounced symptoms include muscle cramping, as the body attempts to maintain fluid and mineral homeostasis by drawing on its own reserves. This chronic deficit can compromise mineral and water metabolism.