If you drink five litres of Coke a day, then stop and drink water instead and feel better, it doesn't mean the water is magic. It's that you're not drinking five litres of Coke a day anymore.
The Chronicle comments that the manufacturers of these machines provide fliers that make various claims: that the water they produce has proven therapeutic benefits for "more than 150 diseases including cancer, diabetes and cardiovascular disease".
Seems to me that making therapeutic claims might be stretching the boundaries of the Medicines Act). And they claim that the water has these effects because it restores the drinker's body to a more alkaline state.
Now, the problem with that particular claim (based, ultimately, on misunderstanding and/or misinterpretation of Otto Warburg's work on tumour metabolism) is that your stomach operates at a low and very acidic pH. Quaff a glass of alkaline water? It'll likely be neutralised when it hits your stomach. In addition, your body's lungs and kidneys maintain tissue pH within a very narrow range; excess hydrogen (H+) or hydroxyl (OH–) ions are excreted in urine, but the tissue pH remains pretty much constant. So those glasses of expensive H2O will keep you nicely hydrated (and feeling good), but they won't be doing much else, and certainly not making changes to your body's tissue pH, though there may be temporary changes in the urine.
Wikipedia has a good article on how these machines actually work. Basically, they are electrolysing tap water as it passes through them.
See earlier story:
Whanganui woman says her $4000 water machine is a life-changer, but experts say otherwise
However the effectiveness of the process is debatable because electrolysis requires significant amounts of time and power; hence, the amount of hydroxide that could be generated in a fast moving stream of water such as a running tap would be minimal at best.
They're also highly unlikely to produce 'hexagonal water' (despite claims from head office, that one is chemical quackery), or significantly affect the oxygenation status of your tap water (another claim about the Kangen machines). Plus, as Ben Goldacre once commented (in a different context), you don't have gills in your gut.
Honestly, there are so many resources out there that assess the claims for alkaline water – and find them wanting – anyone considering buying one of these things would find it easy to some due diligence first. Then, hopefully, you'll put the $4K back in your bank account, and drink a nice glass of chilled tap water.
Dr Alison Campbell is a senior University of Waikato biological sciences lecturer.
