I do not know about Kangen water. But when I tried to understand alkaline water from the guys selling the machine, it is just adding inorganic minerals to the filtered water (from reverse osmosis) to make it alkaline.
Rawbie is right, our body can adjust the pH level in our fluid and blood within a tight range. However, if we consume too much meat or artificial chemical/flavouring/preservatives, it will leach out the alkaline-forming minerals eg calcium from our body (to neutralize the acidity) and cause our blood to be become less alkaline. Eating vegetables and fruits replace those alkaline minerals (after digestion) to help our body remain at the right pH.
Scientifically, pH is measured by the amount of H+ and OH- in the fluid. Acid and alkaline neutralize each other. If we drink alkaline water (with more ionized OH-) into our stomach which is of pH2-3, I would think that it might affect our digestion process since we need the high acidity condition to effectively digest protein. But if we drink fluids that contain lots of alkaline-forming minerals (in organic form, not ionized), after digested and absorbed into our blood, it will help our body to maintain pH balance that it needs.
just share my thoughts...