Purified water is defined as water that has been mechanically processed to remove chemicals, contaminants, and suspended solids, aiming for a very high level of purity. This treatment results in water that is nearly devoid of dissolved substances, including both harmful pollutants and naturally occurring minerals. The physiological effects of consuming purified water are directly related to what has been removed and how the body’s regulatory systems respond to this lack of dissolved content.
How Purification Methods Create Safer Water
The primary benefit of purifying water is the removal of substances that pose a known threat to health. Two common methods are Reverse Osmosis (RO) and distillation. RO systems force water under high pressure through a semi-permeable membrane with extremely small pores. This membrane effectively blocks larger molecules and particles, including heavy metals like lead and arsenic, and various chemical pollutants.
Distillation, an older technique, involves boiling the water and then collecting the steam as it condenses back into liquid form. Since most contaminants, such as salts, minerals, and many organic compounds, have a higher boiling point than water, they are left behind. Both processes are highly effective at eliminating biological contaminants, such as bacteria, viruses, and parasitic cysts. The resulting purified water is microbiologically safe and free from inorganic and organic impurities found in municipal or well water.
The Physiological Effect of Missing Minerals
The purification process strips away naturally occurring trace minerals like calcium and magnesium. While food is the body’s main source of these essential elements, the mineral content in water contributes to overall daily intake.
Exclusive long-term consumption of water lacking these minerals can become a concern if a person’s diet is already deficient. The absence of magnesium in drinking water has been noted in some epidemiological studies related to cardiovascular health. Furthermore, using demineralized water for cooking can cause a measurable loss of minerals from the food itself, with studies showing that up to 60% of calcium and magnesium can leach out of vegetables during preparation.
This lack of dissolved content also impacts the sensory experience of drinking water, as purified water is often described as “flat” or “insipid” due to its low Total Dissolved Solids (TDS) count. The consistent omission of this secondary source can compound deficiencies. The physiological effect is a long-term nutritional consideration that must be balanced by dietary intake.
Purified Water and Electrolyte Balance
The immediate concern is whether purified water can disrupt the body’s delicate electrolyte balance. Electrolytes, such as sodium, potassium, and chloride, are charged minerals that maintain the osmotic pressure necessary for fluid distribution inside and outside of cells. Purified water is considered a hypotonic solution because its concentration of dissolved solutes is significantly lower than that of the body’s internal fluids.
When a hypotonic fluid like purified water enters the bloodstream, it creates a temporary difference in solute concentration. Water molecules will naturally move by osmosis from the area of lower concentration into the body’s cells to achieve equilibrium. This acute cellular swelling is quickly managed by the body’s homeostatic mechanisms.
The kidneys play the primary role in regulating this balance by adjusting the concentration of urine and conserving or excreting excess water and electrolytes as needed. In a healthy individual, the body effectively processes hypotonic water without causing acute electrolyte imbalance or dehydration, provided the individual is consuming sufficient electrolytes through food and other beverages. The myth that purified water actively “leaches” minerals out of the body is negated by the kidney’s precise and continuous regulation of fluid and electrolyte levels.