Minerals in water are much like most things; to be absorbed properly, they need to be balanced with other things. Minerals are alkaline and so they may need a certain level of acidity to be beneficial. This also seems to be true for mineral supplements and alkaline water.
One great solution is organic foods. Organic foods can naturally have the minerals and balancing acidic properties necessary for sufficient absorption. As babies grow into adults, stomach acidity declines. If the necessary acid can’t be gained from diet, supplemental hydrochloric acid is available.
Pangman & Evans expand on the molecular changes concerning minerals in water:
"Water in motion absorbs carbon dioxide and other gases from air. Carbon dioxide forms an organic acid in water known as carbonic acid. It combines with alkaline minerals to create organic mineral complexes that are easily absorbed. The soil also contains organic acids. These are introduced in healthy rivers and streams. In nature, all these organic acids balance alkaline minerals. The resulting water is slightly acidic yet it contains alkaline minerals in a usable, organic form. Nature’s healthy balance for water is slightly acidic—not alkaline."
Added minerals in water may therefore upset the delicate balance provided by nature. Structured water is wonderful for letting the body absorb the minerals naturally.
Reference: “Dancing With Water: The New Science of Water” by MJ Pangman, MS & Melanie Evans