Water ionizers attach directly to your kitchen faucet. The devices will filter water, infuse it with minerals and zap it with an electric current. The result: an alkaline (high pH) brew that, according to manufacturers, is buzzing with free electrons and electrically charged ions. Ionizers, popular in Korea and Japan, are widely available on the Internet.

The claims: Websites selling ionizers often use head-spinning scientific terms such as "negative oxidation reduction potential" and complex diagrams seemingly ripped from college chemistry textbooks. But the basic claims are straightforward. Marketers promote ionized water as a powerful antioxidant that can slow aging and prevent disease. (The "scientific" explanation is that electrons in the water mop up dangerous free radicals produced by oxidation.)

For starters, [Thomas Wheeler] says, any negative ions you drink would immediately bind with positive ions. And even if the negative ions stuck around, they could never act as antioxidants or attack free radicals. "The body relies on molecules like vitamin E and beta carotene for antioxidants. The idea that you could just drink extra electrons is ridiculous."