Thanks for the information.

I've searched and found the japanese agency report (PMDA):
http://www.pmda.go.jp/english/servic..._mar2013_e.pdf

Mineralization was observed on animals but at very high dosis (30mg/kg/day and up). After reading the report it doesn't seem to me more dangerous than a cup of coffee or an aspirin. I recently read that aspirin would not be approved in the US with current regulation. I think that sometimes regulation is less about the patients and more about avoiding lawsuits.