Ionized water is water that has been processed using electricity to change its chemical structure, specifically altering its potential of hydrogen (pH). This process results in a product often marketed to consumers as “alkaline water.” The popularity of this product stems from health claims suggesting it offers benefits beyond what regular tap or bottled water can provide. To evaluate these claims, we must explore how this water is created and the chemical properties that are the focus of its marketing.
The Process of Water Ionization
Ionized water is produced using a specialized appliance called a water ionizer, which employs a technique known as electrolysis. Within the ionizer, water flows into a chamber containing a positive electrode (anode) and a negative electrode (cathode), separated by a membrane. An electric current facilitates an electrochemical reaction that splits the water molecules.
The process depends on water’s natural dissociation into hydrogen ions (\(H^+\)) and hydroxide ions (\(OH^-\)). As water passes through the electrified chamber, positive hydrogen ions are drawn toward the negative cathode, while negative hydroxide ions are drawn toward the positive anode. This movement separates the water into two distinct streams. At the cathode, the water becomes rich in hydroxide ions, leading to alkaline water. Simultaneously, at the anode, oxidation occurs, leading to a surplus of hydrogen ions. This controlled separation mechanism defines electrically ionized water.
The Resulting Alkaline and Acidic Waters
The ionization process yields two types of water with different pH levels and chemical compositions. The water collected from the cathode side is the alkaline output, intended for drinking and marketed for health benefits. This water typically has a pH ranging from 8.5 to 10, higher than neutral water (pH 7).
The second stream, collected at the anode, is the byproduct known as acidic or oxidized water. This water has a low pH, often below 6.0, making it unsuitable for consumption.
Acidic water is sometimes suggested for external uses, such as cleaning or topical applications. The ionizer relies on naturally occurring minerals in the source water, such as calcium and magnesium, which act as electrolytes. These minerals are concentrated in the alkaline stream, contributing to its elevated pH.
Key Chemical Properties Used in Marketing
Marketing focuses heavily on two chemical properties: pH and Oxidation-Reduction Potential (ORP). The pH, or potential of hydrogen, measures the concentration of hydrogen ions in a solution, determining its acidity or alkalinity. Proponents emphasize the higher pH of the alkaline output, suggesting that consuming water with a pH typically between 8.5 and 10 can counteract the perceived acidity of the modern diet.
ORP is a measurement expressed in millivolts (mV) that indicates a substance’s tendency to gain or lose electrons. A positive ORP value signifies an oxidizing agent, while a negative ORP value indicates a reducing agent. Ionized alkaline water is promoted as having a negative ORP, often cited as an antioxidant property.
Manufacturers suggest that a negative ORP allows the water to act as a free radical scavenger, similar to dietary antioxidants. This claimed ability to donate electrons is presented as a mechanism for reducing cellular damage and combating oxidative stress.
Evaluating Health Claims Against Scientific Evidence
Despite the marketing focus on pH and negative ORP, the health claims associated with ionized water are unsubstantiated by independent scientific research. Claims that the water can “balance” or “alkalize” the body’s internal pH are inconsistent with human physiology. The body possesses robust and tightly controlled systems, primarily involving the kidneys and lungs, which maintain the blood’s pH within a very narrow range (7.35 to 7.45) regardless of the pH of consumed water.
Specific claims, such as superior hydration or detoxification, have been the subject of limited studies, often funded by the companies themselves, with inconsistent or minimal results. While some small-scale laboratory experiments suggest that alkaline water with a pH of 8.8 may deactivate pepsin, an enzyme involved in acid reflux, this finding has not been conclusively translated into effective, long-term treatment in human clinical trials.
The scientific community notes a lack of robust, peer-reviewed human trials demonstrating that ionized water provides substantial health benefits beyond those of regular potable water. The measurable changes in the water’s chemical properties do not correlate with the health improvements advertised to consumers. For most people, the body’s homeostatic mechanisms quickly neutralize the slight pH difference, rendering the alkaline property biologically insignificant.