Speaking as a doctoral-level chemist with over a decade of experience spent trying to debunk science myths and demystify science topics, I can say unequivocally that drinking mineral water offers no health benefits over:
* Drinking tap water (technically a form of mineral water);
* Drinking bottled water (which varies greatly in quality);
* Drinking distilled, degassed, millipore-filtered water (arguably, the purest form of water there is).
Mineral water, by definition, is water (H2O molecules) that contains dissolved material. According to the Food and Drug Administration, mineral water is water that contains at least 250 parts per million (ppm) dissolved solids. That means that for every 3999 water molecules, there is an impurity atom of some sort. Often it is sulfur, giving some well water the unpleasant rotten egg odor and taste that many have experienced. A mineral can also be defined as any solid containing a regular structure – a speck of rock, for example. These tiny particles remain suspended in the water, and are usually invisible outside of the laboratory.
By simple definition, mineral water is impure. These impurities can add foul taste (salt, rotten egg flavors) and, depending on the dissolved mineral, can even be unhealthy (lead, chromium, and mercury ions, for example). Think about it for a moment. Do you really want to ingest unknown dissolved solids with your water?
Do human beings require a certain amount of trace minerals to maintain their health? Yes, of course. However, these minerals are needed in such small quantities that anyone with a balanced diet, let alone someone who uses multivitamins, will have absolutely no need to gain these minerals through mineral water, even if such a thing were practical, given the uncertain composition of each batch and brand of said water.
The truth is that people want to believe that they can do something very simple to improve their health. This belief is very powerful, and is pervasive throughout our society. However, by drinking so called mineral water, you are actually taking a significant risk. You have literally no idea of the identity of the dissolved impurities; how could you, without a fairly thorough scientific analysis performed by trained professionals in a well-stocked analytical laboratory?
Drink tap water. It too contains certain minerals, but its safety is monitored by your local waterworks. If the taste is not to your liking, employ an activated carbon filter to your kitchen tap. You’ll be drinking pure, sparkling, largely tasteless, healthy water without ingesting potentially dangerous dissolved solids of a completely unknown nature.
And you’ll save a lot of money in the process.