mineral dissolved in water, water becomes alkaline. The body includes a buffer system that maintains normal ph it doesn't matter how many acidic or alkaline substances will be in a body (e.g. buffer or bicarbonate buffer). Therefore, it doesn't matter how much ionized water drink, you body doesn't become alkaline excessively.

On the contrary, acidification of fluids might cause trouble in your health. For example, Acidification of your body, in which ph value is a lot less than 6.8, because of accumulation of acid materials inside a body received from adult diseases like diabetes or kidney trouble might cause death.