Distilled water is basically water with nothing else in it. That means that there are no dissolved salts and minerals. This is a type of water that a wild animal would never be exposed to. All water found in nature has some salt and minerals dissolved in it, and this is important for something called osmotic regulation. Suffice it to say that this term means how water passes into and out of cells and is regulated, in part, by the dissolved solids in the water. Water routinely passes in and out of cells, which is how the body regulates almost all bodily functions. So, dissolved minerals and salts are very important for normal physiological functions. Distilled water, with no dissolved salts and minerals, cannot support those normal bodily functions.