Alkaline water, also known as alkaline ionized water, is referred to as commercially available water with high pH value. The pH is a measure of the acid-base balance of water. Typically, the pH of natural water ranges between 6.5 and 8.5, and it is controlled by the carbon dioxide-bicarbonate-carbonate equilibrium system.

Litmus strips for measurement of acidity. Image Credit: Guschenkova / Shutterstock

An increase in the amount of dissolved carbon dioxide reduces the pH of water, resulting in acidic water. In contrast, a decreased amount of carbon dioxide increases the pH of water; thus, generating alkaline water.

The pH of water is a major determinant of its corrosivity, which is basically a measure of how destructive water is toward the metals of water distribution systems. Corrosive water has the capacity of dissolving metals, mainly copper and lead, of the plumbing system, which subsequently increases the metal concentration in drinking water, leading to various health-related problems.

Acidic water with pH less than 7 is more corrosive as compared to alkaline water. For this reason, treating the water with alkaline chemicals to increase its pH is considered as one of the best measures of reducing water corrosivity.

Production of Alkaline Water

Alkaline water can be generated by water electrolysis that separates acidic and alkaline components of water. Natural water that flows through rocks also gathers minerals and becomes alkaline in nature. Similarly, electrolyzed water can also be generated from minerals, such as calcium and magnesium, which are highly saturated with hydrogen.

This particular kind of water is known as alkaline reduced water.

Health Benefits of Alkaline Water

Many studies have claimed beneficial health effects of alkaline water consumption. For instance, it has been observed that oral administration of alkaline ionized water causes a reduction in blood levels of glucose, cholesterol, and triglyceride and improves metabolic functioning by suppressing free radical production in mice that are induced with metabolic disorder. It also protects pancreatic beta cells from oxidative damages. Moreover, alkaline water helps in reducing the rate of weight gain in obese mice by regulating cholesterol homeostasis.

In patients with end-stage renal disease, alkaline water has been shown to reduce adverse side-effects of hemodialysis, such as excessive free radical generation. In case of urinary bladder stone, alkaline water accelerates the excretion of melamine and prevents its accumulation in the bladder, which in turn improves the pathological conditions associated with bladder stone.

Since alkaline water has higher pH, its natural capacity of neutralizing acids in the stomach makes it a good choice for treating gastrointestinal tract disorders, such as gastric hyperacidity, diarrhea, etc. In cases of laryngopharyngeal and gastroesophageal reflux diseases, alkaline water has shown to irreversibly inactivate pepsin, an endopeptidase responsible for reflux disease, by neutralizing acid in the stomach.

In case of exercise-induced dehydration in healthy adults, electrolyzed alkaline water has shown to reduce the high-shear blood viscosity, a coefficient to define viscous properties of blood.   
Interestingly, consumption of alkaline water has also shown beneficial effects in promoting longevity. Mice administered with alkaline water have shown better survival rate as compared to their counterparts that are administered with regular water.      

Besides potential health benefits of drinking alkaline water, bathing with it also improves skin-related problems. For example, bathing mice with alkaline water has shown to reduce skin damage associated with UV radiation by maintaining the balance between pro- and anti-inflammatory cytokines.

Is there any Risk?

Despite many advantages of consuming alkaline water, a proper quality control is essential to maintain its pH within physiologically acceptable range. According to the WHO guidelines for drinking water quality, alkaline water with pH greater than 9 causes skin and eye irritation in mice and rabbits. In humans, water with pH higher than 10 causes skin, eye, and mucus membrane irritation; it may also induce gastrointestinal irritation in sensitive persons. Apart from these problems, electrode degradation during the process of water electrolysis may also generate highly reactive platinum nanoparticles, which may also have toxic effects.