One of the greatest perks of a water ionizer is definitely the impact it can have on preventing cancer. Many bodily cancers are caused by oxygen radicals, which are produced as a by-product of various important metabolic functions. 

These radicals are unstable molecules and they attack the cells in the body causing disruptions that can become cancerous.

However, while dangerous, these free oxygen radicals can be combatted with antioxidants, which are produced by an ionizer in the form of Hydroxide ions (OH-). These ions work in a similar way to other good antioxidants such as Vitamins A and C, and they are able to combine with oxygen radicals to form a full oxygen molecule, which can instead by used practically by the body.

Of course this is not a direct cure and it only reduces the risk, but that in itself should be a good enough reason to consider investing as cancer is a problem nobody wants to face.