Home water ionizers, which I've seen offered for sale on the internet, are just the latest twist in the ongoing effort to promote the notion that alkaline water is somehow protective of your health. The underlying idea is that you can prevent disease by balancing your body's pH. Promoters claim that alkaline water is energizing, hydrates the body more effectively than regular water, improves the taste of food when used in cooking, promotes "regularity," helps the body absorb nutrients more effectively, and on and on. I've even seen claims that it can cure everything from obesity and high blood pressure to breast cancer.
None of these claims are true. Furthermore, your body needs absolutely no help in adjusting its pH. Normally, the pH of blood and most body fluids is near seven, which is close to neutral. This is under very tight biological control because all of the chemical reactions that maintain life depend on it. Unless you have serious respiratory or kidney problems, body pH will remain in balance no matter what you eat or drink. As for water, you should consider the fact that alkaline water is common throughout the western states but to my knowledge it has not protected anyone from the diseases and disorders that occur elsewhere in the U.S.
The health claims for water ionizers and for alkaline water are bogus. Save your money.
Andrew Weil, M.D.