Alkaline water is generally considered safe, but it has the potential to produce side effects. It can reduce stomach acid, which may sound like a benefit if you have acid reflux. However, for most healthy people, low levels of stomach acid are likely to cause problems. You could also end up with health issues if you drink too much alkaline water.
Production of Alkaline Water
Most drinking water is neutral, so it's not acidic or alkaline. A device called an ionizer uses electricity to separate the water's hydrogen and oxygen. When a positively charged electrode is put on one side of a water-filled chamber and a negatively charged electrode is on the other side, the electrical current pulls hydrogen atoms to one side of the chamber.
The water on the hydrogen side becomes alkaline, while water on the other side becomes acidic due to the shift in hydrogen ions. A membrane in the middle prevents the two from mixing back together until the water is drained into another container.
Reduce Stomach Acid
Alkaline water neutralizes acids in the stomach. In studies using lab rats, this actually helped prevent aspirin-induced damage to the lining of the stomach, according to BMC Complementary and Alternative Medicine in March 2014.
While the BMC study hints at a positive role for alkaline water, lowering stomach acid isn’t a benefit for most people. You need stomach acid to kill bacteria and other unwanted pathogens so they don’t pass into your bloodstream. Acidity is also essential to properly digest vitamin B-12 and protein.
In laboratory studies, the protein-based enzyme needed to digest protein in the stomach was completely deactivated by alkaline water, reported the Annals of Otology, Rhinology and Laryngology in July 2012.
Most alkaline water made from tap water has a pH in the range of 8 to 11, which is mildly alkaline, reports the Molecular Hydrogen Institute. For comparison, neutral water has a pH of 7 and the pH of liquid drain cleaner is 14.
Alkaline water with a pH higher than 11 may irritate your eyes, skin and mucous membranes. It can also cause gastrointestinal problems, reports the World Health Organization.
Drinking too much alkaline water, or drinking water with a high pH, may disrupt the body’s normal pH. This can lead to a condition called metabolic alkalosis, which may cause confusion, nausea, vomiting, hand tremors, muscle twitching, and tingling in the face, hands or feet.
A study published in August 2001 reported that lab rats receiving alkaline water had lower body weights than rats drinking regular water, according to the International Journal of Experimental Pathology. An earlier study found that young male rats developed heart muscle damage after drinking alkaline water, reported the Journal of Toxicological Sciences in 1998.
These side effects have not been reported in people. In fact, the 2014 report in BMC Complementary and Alternative Medicine stated that hydrogen-rich alkaline water hasn’t caused any side effects in human clinical trials when taken for up to six months. But it’s still important to remember this: Very little evidence exists to date to prove either the benefits or risks of alkaline water.