A topic of considerable debate in recent days is alkalized water. From a chemical point of view this raises both eyebrows and evokes a grin. A review of the meaning of pH might help to explain the absurdity of alkaline—or acidic, for that matter—water. You remember that pH is a measure of acidity or alkalinity of a liquid using a scale that ranges from 0 to 14, with 7 being neutral. Anything below 7 is an acid; above 7 an alkali (base). The fact is that pure water is pH neutral, neither an acid nor a base. Because the pH scale has no upper or lower limit, the range may go below zero or above 14.
If an acid is dissolved in water, the pH will drop. The opposite applies to an alkali. A strong acid, such as hydrochloric (HCL), has a pH of 1.0 or 0.0. Stomach acid contains HCL, and has a pH of 1.0 to 2.0, which is quite strong. Lye—sodium hydroxide—will bring the pH of water up to 14, a very strong base. Because pH is a logarithmic scale, a difference of one pH unit is equivalent to a tenfold change in hydrogen concentration. A low pH indicates a high concentration of hydrogen—or, rather hydronium, the form in which hydrogen exists in solution (a combination of H+ and H2O, making it H3O). This is what determines pH. Pure water has a pH of 7, having an equal number of hydronium and hydroxide (OH) ions. By itself, hydronium is quite acidic at pH -1.7 Yes, negative.
Since pure water is pH neutral, something has to be added to it to change pH. It isn’t the water that’s acidic or alkaline. It’s what’s IN the water that alters the pH. All water has both H+ and OH- ions. More hydrogens yield acidic water; more hydroxides, alkaline. Pure water has equal numbers of each. Add an alkaline mineral, such as calcium or magnesium, and voila, alkaline water. Municipal water generally contains one or both of these, therefore is alkaline.
Electrolysis of water, whereby the H’s and OH’s are separated, is an inefficient process if the water is pure. It’s s-l-o-w, too. But all that does is to separate the H’s from the OH’s near the electrodes, allowing very small excesses of both to build up. Any changes in pH would be barely detectable because the H’s and the OH’s would recombine in a heartbeat. True electrolysis requires the presence of additional ions—the minerals sold to the consumer by the alkaline water machine company. Ordinary salt makes the water more conductive. (Pure water is a very poor conductor.) That salt solution will liberate hydrogen gas at the electrode (cathode) and produce alkaline water consisting essentially of sodium hydroxide (NaOH). At the other electrode, the anode, chloride ions become chlorine, which, if allowed to mix with the hydroxides, will make a disinfectant oxidizing agent called hypochlorous acid, HOCl.
Buying a water ionizer is a costly way to get a product you could make yourself by diluting some laundry bleach. You could adjust the pH with lemon juice. Bleach, by the way, has a pH of about 12.6, quite alkaline. Lemon juice is about 2.2, almost as acidic as stomach acid. The pH of blood runs from 7.35 to 7.45. Change that and you will likely die. Whatever you drink will not affect blood pH because the body knows enough to grab calcium from your bones to neutralize an acidic insult, such as would come from eating too much sugar or too much protein.
If you swallow alkaline water, it will be upset by the acid in your stomach, and the effect you anticipate will not happen. On its way to the large intestine, the place of absorption, your originally alkaline water will meet bicarbonates made by the pancreas and shot into the beginning of the small intestine. Now, regardless of how it went in, the water is alkaline. So, too, is all the food you swallow.
Urinary pH depends on a variety of factors, but is useful only in light of other diagnostic values, so daily pH testing is virtually futile unless you have kidney stones or gout and need to balance pH. If you hold your breath long enough, carbon dioxide will accumulate in the blood and turn the blood acidic. That’s uncomfortable and will force you to breathe, which will return pH to normal. See how the body takes care of itself? We are fearfully and wonderfully made, for sure. But urine is the only body fluid that can have its pH changed by food or supplements, and since it’s stored in the bladder it has no effect on the pH of the rest of the body. It’s true that excess protein, which cannot be stored, breaks down into amino acids that have the capacity to acidify the blood, but the body mobilizes calcium from bone to neutralize it immediately. Lots of clinicians feel that too much protein may cause osteoporosis. Calcium, magnesium, and alkaline water will not change the pH of your blood.
On the other side of this coin is acidic water…for people who don’t want to alkalize. It’s awfully hard to keep some people happy. This contraption is supposed to keep H3O+ in solution. That can’t be done because it needs OH- to remain stable. Want acid water? Try lemon juice. Want alkaline water? Use baking soda, which will give you a pH of 8.3 and taste lousy. Alka-seltzer would work, too.
No placebo-controlled, double-blinded, randomized studies have been found in the scientific literature to support the alkaline water sales pitch. No credible evidence has been found to ascertain the benefits of alkaline water. To be alkaline, water must contain metallic ions of some kind—sodium, calcium, or magnesium is most common.
University of Illinois, Dept. of Chemistry (2011-10-28). Electrolysis of water using an electrical current. http://www.chem.uiuc.edu/clcwebsite/elec.html.
Lower, S. "Ionized" and alkaline water: Snake oil on tap. http://www.chem1.com/CQ/ionbunk.html. Retrieved 2011-10-30.
Hricova D, Stephan R, Zweifel C. Electrolyzed water and its application in the food industry. J Food Prot. 2008 Sep;71(9):1934-47.
Greenwood NN and Earnshaw A (1997) Chemistry of the Elements (2nd ed) Oxford, England: Butterworth-Heinemann
*These statements have not been evaluated by the FDA. These products are not intended to treat, diagnose, cure, or prevent any disease.
May 04, 2012