Brian,
You make an excellent point. When we use the same meds manufactured in different countries to save money in our economic adversity, we raise some of the same issues, sans the contaminants (I hope.) When it comes to vitamins and minerals, including trace minerals, we have had to rely on the Maker above to regulate our doses by this magnificent machine we live in. The government attempts to regulate this with all of their nutrion guidelines and food pyramids, only to discover years or decades later that they, too, were wrong.
Heck, even the U.S. Navy provided guidelines for military scuba divers that the entire world adopted and then they suddenly retracted them after about 50 years and said they may have been dangerous and life-threatening. Go figure.
Ed