you make it sound like its common sense... I get the feeling it may be a little more complex than you are making it. But still thankyou for your reply.
In kinesiology some people go weak with tap water, and yet others remain strong. More often than not those who stay strong, also have a strong faith in God (psalm 91). So when studies are done on the harmfullness of certain elements within the water... IE flouride, I wonder about them. The results of a study done on flouride may show that a certain percent of people get stronger teeth, or a lower immunity. But IMO they are indirectly flawed... because not everyone is the same, but they are assumed to be... even though the study shows otherwise (the fact that everyone does not react the same, shows this asumption doesnt hold water). I think this asumption stems from the newtonian paradigm within western medicine.
This is like the reverse of the placebo effect... where by "toxic" substances which studies are shown to have harmfull effects on people... only have an hazardous effect on a percentage.